Cited by 44Speech Recognition and SynthesisSubtitles and Audiovisual MediaSpeech and Audio Processing

Measuring the Accuracy of Automatic Speech Recognition Solutions

Open access
Kuhn, Korbinian, Kersken, Verena, Reuter, Benedikt, Egger, Niklas, Zimmermann, Gottfried·2023·ACM Transactions on Accessible Computing

Abstract

For d/Deaf and hard of hearing (DHH) people, captioning is an essential accessibility tool. Significant developments in artificial intelligence mean that automatic speech recognition (ASR) is now a part of many popular applications. This makes creating captions easy and broadly available—but transcription needs high levels of accuracy to be accessible. Scientific publications and industry report very low error rates, claiming that artificial intelligence has reached human parity or even outperforms manual transcription. At the same time, the DHH community reports serious issues with the accuracy and reliability of ASR. There seems to be a mismatch between technical innovations and the real-life experience for people who depend on transcription. Independent and comprehensive data is needed to capture the state of ASR. We measured the performance of 11 common ASR services with recordings of Higher Education lectures. We evaluated the influence of technical conditions like streaming, the use of vocabularies, and differences between languages. Our results show that accuracy ranges widely between vendors and for the individual audio samples. We also measured a significant lower quality for streaming ASR, which is used for live events. Our study shows that despite the recent improvements of ASR, common services lack reliability in accuracy.

AI snapshot

Written from the paper’s full text.

TL;DR

This study independently measured Word Error Rate (WER) for eleven common ASR services on Higher Education lecture recordings, finding wide accuracy variation across vendors, samples, languages, and technical conditions. Despite some very low error rates, streaming ASR and non-English/ESL speech performed significantly worse, and confidence outputs did not reliably indicate transcript accuracy.

Key findings

  • Across all vendors on English datasets (batch, no vocabulary), average WER was 7.0%, with individual results ranging from 0% to 53.8%. Table 4 averages were 7.0% for English, 8.6% for LibriSpeech, 10.2% for ESL, and 15.3% for German; Whisper (large-v2) had the lowest averages (2.9%, 3.3%, 3.3%, and 5.0%, respectively).
  • Streaming transcription had a significantly higher WER (10.9%) than batch transcription (9.37%) on English datasets (t(1438)=-1.646, p<0.01; large effect r=0.995).
  • Custom vocabularies did not significantly improve WER: average across eight vendors was 8.61% without vocabulary and 8.10% with vocabulary (t(1438)=-1.646, p=0.640; moderate effect r=0.580), though some technical terms/names appeared only when a vocabulary was provided.
  • Text normalisation strongly affected WER: no transformation averaged 21.83%, lowercase 18.15%, punctuation removal 15.48%, both 11.29%, and extended Whisper/German normalisation 10.16% (simple vs extended: t(2578)=-1.645, p<0.01; large effect r=0.977). Confidence outputs were not transferable to actual accuracy; only AssemblyAI showed an ideal average relation between WER and confidence.

Methods

  • Dataset: 120 audio samples of about 3 minutes each (average 184 s; min 174, max 209), comprising 90 Creative Commons YouTube Higher Education lecture recordings and 30 control samples from LibriSpeech test-other. Four language groups were used: English, ESL, German, and LibriSpeech (English), with 15 male and female speakers per language group.
  • Eleven ASR services were tested: ten commercial vendors (Amazon AWS, AssemblyAI, Deepgram, Google Cloud Platform, IBM Watson, Microsoft Azure, Rev AI, Speechmatics, SpeechText.AI, Tencent Cloud) plus OpenAI Whisper large-v2 as a self-hosted open-source alternative. Each service processed between 180 and 480 transcription jobs depending on supported languages and streaming availability; in total 221 hours of audio were transcribed, yielding 3840 individual transcriptions.
  • Transcription was automated with NodeJS using official SDKs or HTTP/WebSocket APIs, with equivalent configurations across vendors. Reference transcripts were initially produced with Whisper and manually corrected by two independent coders. WER was calculated with the jiwer Python implementation after extensive text normalisation (Whisper normaliser plus German-specific extensions); Welch’s t-tests were used for comparisons.

Limitations

  • The paper states that the Higher Education setting provided rather ideal conditions and avoided particular ASR weaknesses, so results may differ in other environments or for more conversational speech. The dataset reflects biases inherent in online material and the over-representation of certain groups in Higher Education, and findings are restricted to the date of evaluation. The analysis relies on WER as the most common automated metric, which is a limited representation of ASR quality.
  • The text also makes evident that the study covers only English, ESL, German, and LibriSpeech, avoiding challenges such as speaker diarisation, overlapping speech, and mixed language. It does not include qualitative evaluation with DHH individuals, and vendor APIs/models may change over time. Tencent was excluded from streaming transcription due to lacking a WebSocket API, and the authors note possible comparability issues from differing vendor implementation steps.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1145/3636513

Cites

48 of 48 references verified0 citation errors · 0 not checkable

Statistics

3 tests recomputed · 2 with the reported and recomputed p on opposite sides of .05

Claims the paper makes

26 of 77 cited sources checked · 13 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    Some ASR tests produce error rates lower than manual transcription.

    “Some of these tests produce very low error rates that even outperform those achieved through manual transcription [Zhang et al. 2022].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Zhang et al. 2022 source

      Table III in “English (US) Voice Search” (p. 6) reports a 4.1% word error rate, supporting the claim that some ASR tests achieve low error rates. Neither that table nor the passages found by searching for manual transcription and human performance provide a human-transcription error rate, so the claimed comparison is unsupported. (LLM, conf=0.83)

      Experimental — accuracy not yet measured
  • Premisecitation

    Humans create less verbatim transcripts that concentrate on transporting the gist of the text.

    “Humans on the other hand create less verbatim transcripts that concentrate on transporting the gist of the text, but even professional respeakers lag around 20-40 words per minute (wpm) behind the actual speakers [Romero-Fresco 2009].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Romero-Fresco 2009
  • Premisecitation

    Fine-tuning a model for a specific dataset carries the danger of shortcut learning, where a DNN exploits weaknesses in the training data.

    “However Geirhos et al. [2020] show that ine-tuning a model for a speciic dataset carries the danger of shortcut learning, where a DNN exploits weaknesses in the training data.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Geirhos et al. 2020 source

      Section 4.1 (“Dataset: shortcut opportunities”; page unavailable) explains that biases in training data give DNNs opportunities to learn unintended shortcuts. Section 4.2 (“Decision rule: shortcuts from discriminative learning”; page unavailable) says learned features may work only for a particular dataset. These passages support the dataset-specific shortcut risk, but do not specifically address fine-tuning a model. (LLM, conf=0.83)

      Experimental — accuracy not yet measured
  • Premisecitation

    Professional respeakers lag around 20-40 words per minute behind actual speakers.

    “even professional respeakers lag around 20-40 words per minute (wpm) behind the actual speakers [Romero-Fresco 2009].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Romero-Fresco 2009
  • Premisecitation

    ASR and professional transcribers produce quite different results due to their inherent strengths and weaknesses.

    “It is important to note that the results of ASR and professional transcribers are quite diferent due to their inherent strengths and weaknesses [Romero-Fresco 2009].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Romero-Fresco 2009

      Section 5.1 describes a workflow in which a professional respeaker speaks into speech-recognition software; it does not compare ASR output with transcripts produced separately by professionals. The Conclusions discuss the strengths and limitations of respoken subtitles, but do not attribute different results to the inherent strengths and weaknesses of ASR versus professional transcribers. Searched for that comparison and for the two groups’ respective strengths and weaknesses. (LLM, conf=0.74)

      Experimental — accuracy not yet measured
  • May combine two claims. 64
  • Classified as probably not a substantial claim. 114
  • The quote only partly states this claim. 3
  • May combine two claims.

    Premisecitation

    Prior studies aim to show specific ASR biases affecting underrepresented groups but do not address overall engine accuracy.

    “The studies aim to show that ASR has speciic biases that often afect speakers of underrepresented groups, but are not concerned with the overall accuracy of the engines.”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites Cumbal et al. 2021 source

      The Introduction states that the paper aims to examine the recognition gap between native and non-native Swedish speakers, supporting the claim about group-specific ASR performance. But §5.1 (Performance) says the authors evaluate each ASR using word error rate, and §6.1 compares the engines’ results. The claim that the study is not concerned with engine accuracy is therefore too absolute. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites Koenecke et al. 2020 source

      The Results report substantially higher word error rates for Black than white speakers across five commercial ASR systems, supporting the claim about bias affecting an underrepresented group. But the same section compares the systems’ overall performance, identifying Microsoft as best and Apple as worst, so the claim that the study was not concerned with engine accuracy is unsupported. No page number is available in our copy. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites Speechmatics 2023

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Training and optimizing for specific datasets risks overfitting, so results may not indicate performance on novel datasets.

    “Training and optimisation for speciic datasets bear the risk of overitting, and the obtained results might not be a good indicator of performance on novel datasets [Geirhos et al. 2020].”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Geirhos et al. 2020 source
  • May combine two claims.

    Premisecitation

    ASR performance varies across datasets and speaker groups, including by gender, race, and accent.

    “Many sources show ASR's volatility with diferent datasets: ASR performs diferently for male or female speakers, shows racial biases or varying accuracy rates for speakers with diferent accents [Cumbal et al. 2021;Koenecke et al. 2020;Speechmatics 2023;Tadimeti et al. 2022;Tatman and Kasten 2017].”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites Cumbal et al. 2021 source

      Section 6.1 (page unavailable) reports different word error rates for native and non-native Swedish speakers and for speakers with different first languages; Table 2 also shows variation across datasets. These passages support the dataset and accent-related portions of the claim, but our copy does not substantiate the claims about gender differences or racial bias. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites Koenecke et al. 2020 source

      The Results report different error rates by race and gender (passages 1 and 7), and associate error rates with AAVE dialect density and pronunciation differences (passages 4 and 6). The Discussion (passage 8) suggests that speakers with regional or nonnative-English accents may also face poor performance, but does not establish varying accuracy rates across those accent groups. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites Speechmatics 2023

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

    Premisecitation

    Evaluation of an ASR system heavily depends on the use-case, and various factors have to be considered.

    “Evaluation of an ASR system heavily depends on the use-case, and various factors have to be considered [Aksënova et al. 2021].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Aksënova et al. 2021 source
  • May combine two claims.

    Premisecitation

    Training a model on multiple public speech datasets results in comparable accuracy but higher robustness than models trained on a single source.

    “Chan et al. [2021] show that training a model on multiple public speech datasets results in a comparable accuracy but higher robustness than models trained on a single source.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Chan et al. 2021 source

      The Introduction (p. 1) describes training one model on combined speech datasets and reports results that compare favourably with prior work; the Experiments (p. 3) include single-domain results for comparison. The paper also reports strong transfer to a new dataset, but it does not establish that the mixed-data model is more robust than models trained on a single source. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Evaluating ASR systems on multiple public speech datasets results in an average End-to-End Speech Benchmark (ESB) score.

    “Respectively [Gandhi et al. 2022] propose to evaluate ASR systems on multiple public speech datasets resulting in an average End-to-End Speech Benchmark (ESB) score.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Gandhi et al. 2022 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The quality of ASR in poor acoustic environments has greatly improved, e.g. accuracy in noisy environments.

    “The quality of ASR in poor acoustic environments has greatly improved, e.g. the accuracy in noisy environments [Kinoshita et al. 2020].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Kinoshita et al. 2020 source
  • Classified as probably not a substantial claim.

    Study design and conductcitation

    The authors used the Whisper text normaliser, which transforms text to lowercase, removes all punctuation, and unifies common contractions, spelling differences and spoken numbers.

    “We used the Whisper text normaliser [Radford et al. 2022], which transforms text to lowercase, removes all punctuation, and uniies common contractions, spelling diferences and spoken numbers.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Radford et al. 2022 source

      Appendix C, Text Standardization (p. 21), describes the Whisper normalizer’s handling of contractions, British and American spellings, and spoken numbers. It does not list lowercasing among the English normalization steps, and its punctuation-removal rules preserve characters used in numeric expressions; the claim that it removes all punctuation is therefore too broad. Lowercasing is explicitly listed for non-English text. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A prior study indicates that speakers adjust their behaviour in meetings with DHH peers when ASR is used.

    “A prior study indicates that speakers adjust their behaviour in meetings with DHH peers when ASR is used [Seita et al. 2018].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Seita et al. 2018 source
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Focus groups can provide ideas on how to improve the use of ASR or help assess the acceptance of new features like automatic content summarisation.

    “Focus groups can also provide ideas on how to improve the use of ASR [Seita et al. 2022], or help assess the acceptance of new features like automatic content summarisation [Alonzo et al. 2020].”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Seita et al. 2022 source
    • cites Alonzo et al. 2020 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The CER may be useful for evaluating languages that do not separate words with spaces, such as Chinese.

    “The CER may be useful for evaluating languages that do not separate words with spaces, such as Chinese [Radford et al. 2022].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Radford et al. 2022 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A related study reported a speed increase of up to twelve times without sacrificing transcription accuracy.

    “A related study reported a speed increase of up to twelve times without sacriicing transcription accuracy [Bain et al. 2023].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Bain et al. 2023 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    These findings are also reported by other studies.

    “These indings are also reported by other studies [AssemblyAI 2023;Hughes 2023;Radford et al. 2022;Stephenson 2022].”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites AssemblyAI 2023

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Hughes 2023

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Radford et al. 2022 source

      The citing sentence does not identify what “these findings” refers to, so there is no specific result to compare with Radford et al. Section 5 (p. 13) discusses a finding replicated across fields, and Section 4.3 (p. 11) reports transfer results, but the supplied sentence does not establish that either is the finding being cited. (LLM, conf=0.72)

      Experimental — accuracy not yet measured
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Prior research reports WER measurements for several of the vendors included in this study.

    “Summary of Word Error Rate measurements of diferent services from related research”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites Addlesee et al. 2020 source
    • cites Ballenger 2022

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Catania et al. 2019 source
  • May combine two claims.

    Findingown data

    The accuracy of the eleven ASR services varied widely between vendors and across individual audio samples.

    “Our results show that accuracy ranges widely between vendors and for the individual audio samples.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingcitation

    Some vendors used public datasets to test the accuracy of their ASR engines, while others referred to internal datasets.

    “While some vendors used public datasets to test the accuracy of their ASR engines (SpeechText.AI [SpeechText.AI 2023], Rev AI [Jette 2020], Speechmatics [Hughes 2023], AssemblyAI [AssemblyAI 2023]), others referred to internal datasets (Deepgram [Stephenson 2022]).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites SpeechText.AI 2023

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Jette 2020

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Stephenson 2022

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingown data

    Common cloud providers Amazon, Google, IBM and Microsoft appear in multiple studies, while specialised ASR providers are less represented.

    “While the common cloud providers Amazon, Google, IBM and Microsoft appear in multiple studies, specialised ASR providers are less represented.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingnone given

    Some vendors require additional steps like uploading files to a cloud bucket, while others handle multiple steps within a single HTTP-Call.

    “Some vendors require additional steps like uploading iles to a cloud bucket, while others handle multiple steps within a single HTTP-Call (e.g.transcription with a custom vocabulary).”
    Quote in the paperNot a substantial claim
  • The quote only partly states this claim.

    Findingown data

    The average WER of the eight vendors offering custom vocabulary across the English datasets was 8.61% without a vocabulary.

    “The average WER of these providers across the English datasets was 8.61%.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    On average, native English speakers achieved the lowest error rates and ESL speakers performed better compared to German Native Speakers.

    “On average native English speakers achieved the lowest error rates and ESL speakers performed better compared to the results for German Native Speakers.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data

    Both the average accuracy and standard deviation of error rates varies between the vendors.

    “The results show that both the average accuracy and standard deviation of error rates varies between the vendors.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    Some APIs offer the functionality to upload custom vocabularies before the actual transcription.

    “Some APIs ofer the functionality to upload custom vocabularies before the actual transcription.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data

    For the 30 different samples, seven different vendors achieved the highest accuracy and three different vendors for the lowest accuracy.

    “For the 30 diferent samples, we counted seven diferent vendors that achieved the highest accuracy and three diferent vendors for the lowest accuracy.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The average wpm is 148 (min 94, max 222).

    “The average wpm is 148 (min 94, max 222).”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    The dataset has an even distribution of male and female speakers.

    “The dataset has an even distribution of male and female speakers”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Findingnone given

    All audio samples are around three minutes long.

    “as all audio samples are around three minutes long.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The samples have an average duration of 184 seconds (min 174, max 209).

    “The samples have an average duration of 184 seconds (min 174, max 209).”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Some vendors did not provide all technical requirements e.g. custom vocabularies, streaming or specific combinations.

    “Some vendors did not provide all technical requirements e.g.custom vocabularies, streaming or speciic combinations (e.g.German streaming with a custom vocabulary).”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data

    Whisper has the highest accuracy and longest processing duration.

    “Whisper has the highest accuracy and longest processing duration”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The number of spoken words is 455 on average (min 287, max 671).

    “The number of spoken words is 455 on average (min 287, max 671).”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data

    The lowest calculated WER value was 0% and the highest 53.8%.

    “The lowest calculated value was 0% and the highest 53.8%.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data

    The average and standard deviation of Word Information Lost are around 30% higher than WER.

    “they are around 30% higher for the Word Information Lost (M=0.152,SE=0.118).”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    The samples do not contain strong accents.

    “Even though the samples do not contain strong accents”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Providing a vocabulary increased the vocabulary-word hits for all vendors except Tencent.

    “The hits increased for all vendors except Tencent when providing a vocabulary.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data

    Samples of non-native speakers show higher error rates for English, but still perform better compared to the German dataset.

    “While the samples of non-native speakers show higher error rates for English, they still perform better compared to our German dataset.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data

    Whisper as an open-source model outperforms commercial services in many cases and reports quite low error rates in general.

    “Whisper as an open-source model outperforms commercial services in many cases and reports quite low error rates in general.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    For all vendors, the majority of vocabulary-word hits were already counted without providing a vocabulary.

    “For all vendors the majority of hits was already counted without a vocabulary.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    No vendor reached the maximum number of vocabulary-word hits according to the reference transcript.

    “No vendor reached the maximum hits according to the reference transcript.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    ASR performs notably better for English and German compared to many other languages.

    “Furthermore, ASR performs notably better for English and German compared to many other languages.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims. The quote only partly states this claim.

    Findingown data

    Several transcription problems were encountered, including differences between UK and US spelling, common contractions, and currency writings.

    “We encountered several problems during transcription, such as diferences between UK-and US-spelling, common contractions”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims. The quote only partly states this claim.

    Findingown data

    Whisper (large-v2) had the lowest average WER on each dataset: 2.9 on English LibriSpeech, 3.3 on ESL, 3.3 on German, and 5.0 on average.

    “| Whisper (large-v2) | 2.9 | 3.3 | 3.3 | 5.0 |”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data

    The study confirmed very high accuracy rates in some cases, but found a wide range in quality across vendors, speakers and languages.

    “We could conirm very high accuracy rates in some cases, but found a wide range in quality across vendors, speakers and languages.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingnone given

    Alternative error metrics showed similar results compared to the WER and seem to be interchangeable.

    “Alternative error metrics showed similar results compared to the WER and seem to be interchangeable.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingnone given

    Whisper with condition_on_previous_text enabled hallucinated and created longer transcripts than the actual file.

    “as it hallucinated and created longer transcripts than the actual ile.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Tencent did not provide confidence values.

    “Tencent did not provide conidence values.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Findingnone given

    Transcribing correct punctuation is difficult for spoken language and influences capitalization.

    “Additionally, transcribing correct punctuation is diicult for spoken language and inluences capitalization”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    The average WER across vendors was 7.0 for English LibriSpeech, 8.6 for ESL, 10.2 for German, and 15.3 overall.

    “| Average | 7.0 | 8.6 | 10.2 | 15.3 |”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The NAD proposes to regulate the use of ASR and the metrics used to specify caption and transcript accuracy.

    “The NAD proposes to regulate the use of ASR and the applied metrics to specify accuracy of captions and transcripts.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Blake 2019

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    After an initial transcription using Whisper, the transcript was manually corrected to create an error-free reference and a vocabulary list.

    “After an initial transcription using Whisper (4), the transcript was manually corrected (5) to create an error-free reference and a vocabulary list.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    Despite criticism, the WER is still useful to evaluate and compare ASR systems.

    “Despite the criticism, the WER is still useful to evaluate and compare ASR systems.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationreasoning

    As ASR systems produce verbatim transcripts, a word-by-word comparison is suitable and an analysis in terms of content becomes less relevant.

    “As these systems produce verbatim transcripts, a word by word comparison is suitable and an analysis in terms of the content becomes less relevant.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: AI is good at keeping up with the speed of speech and creates almost verbatim transcripts.
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Speech can be up to ten times faster than typing, making manual transcription laborious.

    “Manually creating accurate transcripts for spoken language is a laborious task, as speech is up to ten times faster than typing [Wald 2006].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Wald 2006 source
  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisereasoning

    Heavily accented speech is challenging for ASR systems because it contains acoustic and linguistic markers of both the source and target language, and could thus be the source of transcription errors.

    “We used these criteria because heavily accented speech is challenging for ASR systems, as it contains acoustic and linguistic markers of both the source and target language, and could thus be the source of transcription errors.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisereasoning

    Transcription of real-time events is more challenging because there is no time to replay audio and only a small window to correct texts.

    “Transcription of real-time events is even more challenging, as there is no time to replay audio, and there is only a small window of time to correct texts.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductreasoning

    The transcription process was fully automated using equivalent configurations across different vendors to provide high comparability.

    “To provide a high comparability of results, the transcription process was fully automated, using equivalent conigurations across diferent vendors.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The FCC requires captions to match spoken words to the fullest extent possible and distinguishes between pre-recorded and live captioning rules.

    “The Federal Communications Commission (FCC) requires captions to match the spoken words to the fullest extent possible, and additionally states that their rules on captioning distinguish between pre-recorded media and live transcriptions [Federal Communications Commission 2014].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Federal Communications Commission 2014

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    WER was calculated after extensive text normalisation to reduce errors caused by non-semantic differences.

    “The WER was calculated after extensive text normalisation to reduce errors caused by non-semantic diferences.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductnone given

    The dataset was created to reflect ASR performance with minimal bias and without targeting specific weaknesses.

    “We created a novel dataset that attempts to relect the performance of ASR with minimal bias and without targeting speciic weaknesses.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    A new dataset was created to minimise the risk that samples were part of an ASR model's training data, which could lead to artificially good performance.

    “To achieve this objective, a new dataset was created to minimise the risk of samples being part of an ASR model's training data, which could lead to a particularly good performance.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationreasoning

    The WER values of different ASR studies are not comparable to each other because error rates depend on the tested dataset, the date of the test, and the degree of text normalisation used to calculate WER.

    “The values of each study are not comparable to others, as the error rates depend on multiple factors: (1) the tested dataset, (2) the date of the test, and (3) the degree of text normalisation to calculate the WER.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning

    Limited availability of transcription professionals is a big issue.

    “Besides the complexity of this task and high operational costs, a big issue is the limited availability of these professionals.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductcitation

    The quality of all speech recordings was measured with MOSNet and only recordings with an absolute value of 2 or higher were selected.

    “We additionally measured the quality of all speech recordings with MOSNet and selected only recordings with an absolute value of 2 or higher [Lo et al. 2019].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Lo et al. 2019

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The majority of DHH individuals tend to favour the comprehensive access offered by verbatim texts.

    “the majority of DHH individuals tend to favour the comprehensive access ofered by verbatim texts [National Institute on Deafness and Other Communication Disorders 2017].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites National Institute on Deafness and Other Communication Disorders 2017

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductnone given

    Recordings with very professional setups or bad audio quality were avoided.

    “We avoided recordings with either very professional setups, or bad audio quality (e.g.strong reverberation, noise interferences, unintelligible or barely audible speech).”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Only videos with average audio quality representative of a Higher Education setting were selected.

    “We selected only videos with an average audio quality, that (we think) is representative of a Higher Education setting (e.g.speakers using a clip-on microphone).”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Within six years, the most accurate models could decrease the WER down to 2.5%.

    “Within only six years, the most accurate models could decrease the WER down to 2.5% [Meta AI 2023].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Meta AI 2023

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Accessible transcription incorporates issues beyond text accuracy, such as placement of captions, correct speaker identification, and presence of relevant non-speech information.

    “Besides text accuracy, accessible transcription incorporates other issues like the placement of captions, correct speaker identiication or the presence of relevant non-speech information [Federal Communications Commission 2014;Lawton Henry et al. 2022].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Federal Communications Commission 2014

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Lawton Henry et al. 2022

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Prior to calculating WER, the ASR transcript and the reference transcript were normalised.

    “Prior to calculating the WER, the ASR transcript and the reference transcript were normalised.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    Human-generated transcripts can be easier to read than ASR results but can also miss important information.

    “Even though the transcript might be easier to read than results from ASR, it can also miss important information.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Study design and conductnone given

    The initial selection of videos was rated in a two step review process by three members of the team with regard to recording quality, accent, intelligibility, and High German without strong accents.

    “This initial selection of videos was then rated in a two step review process by three members of the team with regard to the following criteria:”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    All videos that had manually created or corrected captions were excluded because they might be part of the training data of Whisper and other services.

    “We also excluded all videos that had manually created or corrected captions, as these might be part of the training data of Whisper and other services.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The LibriSpeech corpus is a widely used benchmark in science and industry.

    “The LibriSpeech corpus [Panayotov et al. 2015] is a widely used benchmark in science and industry.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Panayotov et al. 2015 source
  • May combine two claims.

    Premisecitation

    The WER does not reflect text understanding and only weakly correlates with human judgement of a transcript's quality.

    “But the WER has been criticised, as it does not relect text understanding, and only weakly correlates with human judgement of a transcripts' quality [Favre et al. 2013;Mishra et al. 2011;Wang et al. 2003].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Favre et al. 2013 source
    • cites Mishra et al. 2011 source
    • cites Wang et al. 2003

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The FCC requires that online captions must be verbatim, and paraphrasing should be minimised for realtime transcription.

    “The FCC also requires that oline captions must be verbatim, and paraphrasing should be minimised for realtime transcription [Federal Communications Commission 2014].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Federal Communications Commission 2014

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationnone given

    ASR does not distinguish between skin colours, but reflects biases in the training data.

    “Obviously, ASR does not distinguish between skin colours, but relects biases in the training data.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    With LibriSpeech release in 2015, first models reported a WER of 13.25%.

    “With its release in 2015 the irst models reported a WER of 13.25%.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Panayotov et al. 2015 source
  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    When companies publish data on the accuracy of their ASR services, it is not always clear whether these serve the purpose of advertising or a favourable comparison to other vendors.

    “When companies publish data on the accuracy of their ASR services, it is not always clear whether these serve the purpose of advertising or a favourable comparison to other vendors.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Premisecitation

    W3C WAI states that ASR-generated captions do not meet accessibility requirements unless confirmed fully accurate.

    “However the W3C Web Accessibility Initiative (WAI) is a bit more speciic by stating that ASR-generated captions do not meet accessibility requirements unless they can be conirmed to be fully accurate [Lawton Henry et al. 2022].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Lawton Henry et al. 2022

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisereasoning

    The Higher Education scenario is suitable for evaluating ASR because it contains specialist vocabulary and lecturers are not professional speakers.

    “The scenario of Higher Education is also suitable, as it contains specialist vocabulary and lecturers are used to presenting without being professional speakers.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: There is a high demand for affordable and scalable transcription of lectures, talks and other learning formats in Higher Education.
    • Rests on an assumption: Higher Education institutions are required to offer equal access to all students, and transcription of lectures is essential for that, benefiting DHH students, language learners, and remote students.
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Trained professionals are needed to accurately transcribe live events.

    “Thus, trained professionals are needed to accurately transcribe live events.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Premisecitation

    WCAG only specifies that captions are provided, without clearly defined accuracy requirements.

    “The Web Content Accessibility Guidelines (WCAG) only specify that captions are provided, without clearly deined requirements for accuracy [Adams et al. 2022].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Adams et al. 2022

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisereasoning

    Both CART and respeaking are very demanding, requiring multiple professionals for longer events.

    “As both methods are very demanding, multiple professionals are required for longer events to give the operators rest periods.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    ACE might not be suited for scenarios other than conversational speech, such as Higher Education or Entertainment.

    “ACE for example is trained on conversational speech and thus might not be suited for other scenarios like Higher Education or Entertainment.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: ACE is trained on conversational speech.
  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    The lower the WER is, the closer the produced transcript is to the actual text, and fewer errors should result in high levels of understandability.

    “The lower the WER is, the closer the produced transcript is to the actual text -fewer errors should therefore result in high levels of understandability.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    Only parts of recordings where only the presenter speaks were chosen, to avoid additional issues like speaker diarisation.

    “We only chose parts of recordings, where only the presenter speaks, to avoid additional issues like speaker diarisation.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning

    Demand for transcription of events is increasing as more digital content is produced.

    “At the same time, as more digital content is produced in the form of online presentations and remote meetings, the demand for transcription of events is increasing.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Bias in ASR applies to all kinds of dimensions.

    “Bias in ASR applies to all kinds of dimensions.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The FCC requires that capitalisation and punctuation is included in accurate captions, as these influence an individual's understanding of the text.

    “The FCC requires that capitalisation and punctuation is included in accurate captions, as these inluence an individual's understanding of the text [Federal Communications Commission 2014].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Federal Communications Commission 2014

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The authors selected content covering a wide area of topics to limit bias in the dataset.

    “We try to limit this bias by selecting content that covered a wide area of topics from Computer Science, Electrical Engineering and Chemistry to History, Sociology, Politics, Linguistics, Religion and Neuroscience.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The study has four different technical scenarios: batch or stream transcription and with or without an additional custom vocabulary.

    “Additionally, we have four diferent technical scenarios: batch or stream transcription and with or without an additional custom vocabulary.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The study has four language groups: English, ESL, German and LibriSpeech (English).

    “We have four language groups: English, ESL, German and LibriSpeech (English).”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Results might be different for more spontaneous, conversational, and colloquial speech.

    “As our samples are recordings in the context of Higher Education, results might be diferent for more spontaneous, conversational, and colloquial speech.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Study design and conductown data

    The authors randomly selected a part of each video that had continuous and fluent speech.

    “We randomly selected a part of each video that had continuous and luent speech (e.g.no interactions with the audience or writing on a board).”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Study design and conductnone given

    The audio was converted to a standardised format that all vendors supported (44,100 Hz, mono, PCM 16-bit, LE).

    “The audio was converted to a standardised format that all vendors supported (44,100 Hz, mono, PCM 16-bit, LE).”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The authors always used the closest region to their location if cloud vendors offered multiple regions.

    “We always used the closest region to our location (e.g.eu-central), if cloud vendors ofered multiple regions.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    The lower results of AssemblyAI and Tencent could indicate an optimisation towards the LibriSpeech corpus.

    “The lower results of AssemblyAI and Tencent could indicate an optimisation towards the LibriSpeech corpus.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Two independent coders manually corrected each transcript.

    “Two independent coders manually corrected each transcript.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning

    As punctuation was removed for the calculation of the WER, the authors only used confidence outputs from an API on words and excluded punctuation marks.

    “Consequently as punctuation was removed for the calculation of the WER, we only used conidence outputs from an API on words and excluded punctuation marks.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    It is difficult to assess ASR's ability to provide accessible transcripts, as it depends on a case-by-case basis.

    “This makes it diicult to assess ASR's ability to provide accessible transcripts, as it depends on a case-by-case basis.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    Our findings do not necessarily disprove other studies that report higher error rates, as WER is heavily dependent on the degree of text normalisation.

    “However, our indings do not necessarily disprove other studies that report higher error rates (see Table 2), as the WER is heavily dependent on the degree of text normalisation.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The authors could not rule out the possibility that a repeated transcription of the same audio file influences the result of the second run (e.g., faster processing time through caching), except for Whisper.

    “We could not rule out the possibility that a repeated transcription of the same audio ile inluences the result of the second run (e.g.faster processing time through caching), except for Whisper.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The authors did not select ESL speakers from countries or regions that might have English as an official government language (e.g., India or Nigeria), as they might be more fluent or completed their education in English.

    “However, we did not select speakers for the ESL samples from countries or regions that might have English as an oicial government language (e.g.India or Nigeria), as they might be more luent or completed their education in English.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductreasoning

    The authors used the jiwer Python implementation to calculate the WER, and applied extensive text transformation to all transcripts to reduce the impact of formatting differences on the error rate.

    “We used the jiwer [Vaessen 2023] Python implementation to calculate the WER, and applied extensive text transformation to all transcripts to reduce the impact of formatting diferences on the error rate.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Vaessen 2023

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Previous research suggests using ASR as a basis for manual corrections to create more accurate transcripts compared to a fully manual approach.

    “Previous research suggests using ASR as a basis for manual corrections to create more accurate transcripts compared to a fully manual approach [Che et al. 2017].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Che et al. 2017 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    The volume of the audio was normalised with sox.

    “Additionally, the volume of the audio was normalised with sox [Bagwell 2023].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Bagwell 2023

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given

    ASR engines are only trained on limited datasets that do not include other variants of English, which could lead to or enforce existing biases.

    “It is a general problem that ASR engines are only trained on limited datasets that do not include other variants of English as this could lead to or enforce existing biases.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The authors selected ESL samples with different accents (European, South American, Asian).

    “We selected samples with ESL speakers who had diferent accents (European, South American, Asian).”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    In the case of Tencent, the authors had to exclude all words that exceeded the limit of ten characters.

    “In the case of Tencent, we had to exclude all words that exceeded the limit of ten characters.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning

    The different approaches might affect the measured timings and are considered for a comparative analysis.

    “The diferent approaches might afect the measured timings and are considered for a comparative analysis.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    In a few cases, the authors had to restart a transcription job due to an HTTP or API error, and had no issues after a second try.

    “In a few cases, we had to restart a transcription job, as an HTTP or API error occurred.We had no issues after a second try.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The dataset is not specifically designed to examine gender differences in ASR accuracy.

    “but is not speciically designed to examine gender diferences in ASR accuracy.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The authors extended the normalisation for German according to common contractions and numbers appearing in the transcripts of their dataset.

    “We extended the normalisation for German according to common contractions and numbers appearing in the transcripts of our dataset.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The authors chose 15 male and female speakers per language group.

    “We chose 15 male and female speakers per language group.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisereasoning

    ASR engines are often trained on datasets with RP or GenAm, and samples with a large difference from this training set could produce more errors.

    “Similarly, ASR engines are often trained on datasets with RP or GenAm.Samples with a large diference from this training set, could produce more errors.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Study design and conductnone given

    The control recordings fulfil the same criteria as the English videos with regard to speaker accents and audio length.

    “The recordings fulill the same criteria as the English videos with regard to speaker accents and audio length.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Acceptance of ASR as an accessible accommodation is an important factor, as it can be perceived as a second-rate service by users.

    “Acceptance of ASR as an accessible accommodation is an important factor, as it can be perceived as a second-rate service by users [National Deaf Center on Postsecondary Outcomes 2020].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites National Deaf Center on Postsecondary Outcomes 2020

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The authors carefully looked out for Whisper-specific errors such as the removal of duplicate words.

    “we carefully looked out for Whisper speciic errors like the removal of duplicate words.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationreasoning

    The quality most likely decreases for languages with a smaller corpus of training data and more complex languages.

    “The quality most likely decreases for languages with a smaller corpus of training data, and more complex languages, e.g.languages with a number of grammatical cases, articles or capitalisation of nouns.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning

    Results may differ in other environments or for more conversational speech.

    “Results may difer in other environments or for more conversational speech.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Study design and conductnone given

    All API parameters of each vendor were checked to assure comparability and to avoid unintentional default settings.

    “We checked all API parameters of each vendor to assure comparability and to avoid unintentional default settings.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationreasoning

    The WER cannot be used exclusively, as text normalisation removes important aspects of punctuation or capitalisation, and other factors such as speaker diarisation or caption formatting are not covered.

    “However, it cannot be used exclusively, as text normalisation removes important aspects of punctuation or capitalisation, and other factors such as speaker diarisation or caption formatting are not covered.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    Given the variety of ASR applications, a single metric is insufficient to comprehensively represent the quality of an ASR model.

    “Due to the variety of applications of ASR, a single metric appears insuicient to comprehensively represent the quality of an ASR-model.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationown data

    Most of the tested ASR services seem to have a robust general performance, and do not only achieve particularly good results on a common dataset.

    “Most of the tested ASR services seem to have a robust general performance, and do not only achieve particularly good results on a common dataset.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    If vendors provided multiple models, the model that promised the highest accuracy was selected.

    “If vendors provided multiple models, we selected the model that promised the highest accuracy.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning

    The findings are restricted to the date of the evaluation, as AI is a rapidly changing area of research.

    “The indings are also restricted to the date of the evaluation, as AI is a rapidly changing area of research.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: AI is a rapidly changing area of research.
  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    Despite criticism that the WER does not necessarily reflect the usefulness of a text, it still holds potential as a complementary accessibility metric.

    “Despite criticism that the WER does not necessarily relect the usefulness of a text [Favre et al. 2013;Mishra et al. 2011;Wang et al. 2003], it still holds potential as a complementary accessibility metric.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Favre et al. 2013 source
    • cites Mishra et al. 2011 source
    • cites Wang et al. 2003

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • Rests on an assumption: ASR continues to improve and error rates decrease, making metrics based on a string edit distance more robust.
    • Rests on an assumption: The WER is objective, unbiased, and commonly used as an evaluation metric in ASR research.
  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Study design and conductnone given

    The setting chosen, Higher Education, provided rather ideal conditions and avoided particular weaknesses of ASR.

    “The setting we chose, Higher Education, provided rather ideal conditions and avoided particular weaknesses of ASR.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S2 (checkable), S4 (based). May combine two claims.

    Interpretationnone given

    Only because ASR offers a solution for the complex task of transcription, it is not necessarily accessible and enables DHH individuals to participate in various events.

    “But only because ASR ofers a solution for the complex task of transcription, it is not necessarily accessible and enables DHH individuals to participate in various events.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Premisecitation

    Accuracy is not the only relevant factor for ASR, and E2E-models have shown weaknesses in streaming capabilities, latency and computational efficiency.

    “However, accuracy is not the only relevant factor for ASR, and E2E-models have shown weaknesses in streaming capabilities, latency and computational eiciency [Li 2022].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Li 2022

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationown data

    It is very likely that Deepgram uses a split-and-merge approach to increase processing speed, given its very fast performance in the evaluation.

    “It is very likely that Deepgram uses such an approach, given its very fast performance in our evaluation.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationown data

    The WER is particularly useful for verbatim transcription, and extensive text normalisation can reduce errors caused by non-semantic differences.

    “The WER is particularly useful for verbatim transcription, and extensive text normalisation can reduce errors caused by non-semantic diferences.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Premisereasoning

    Because text normalisation is used to reduce non-semantic differences, information about the correctness of punctuation and capitalisation is lost from WER.

    “but because text normalisation is used to reduce non-semantic diferences, information about the correctness of punctuation and capitalisation is lost.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Study design and conductnone given

    The chosen scenario avoided many of the challenges of ASR, such as speaker diarisation, overlapping speech and mixed language.

    “Our chosen scenario avoided many of the challenges of ASR, such as speaker diarisation, overlapping speech and mixed language.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    WER currently serves as the standard metric for reporting ASR accuracy.

    “Currently, the WER serves as the standard metric for reporting accuracy”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    To receive verbatim transcripts, all filters (e.g. profanity) were disabled.

    “To receive verbatim transcripts, we disabled all ilters (e.g.profanity).”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    There is no guarantee that any of these words will be correctly identified and transcribed by an ASR-model.

    “even though there is no guarantee that any of these words will be correctly identiied and transcribed by an ASR-model.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Study design and conductnone given

    The dataset reflects biases inherent in the material available online and the over-representation of certain groups in Higher Education.

    “Furthermore, our dataset relects biases inherent in the material available online and the over-representation of certain groups in Higher Education.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning

    The analysis relies on the WER as the most common automated metric, which is a limited representation of ASR quality.

    “Due to the large amount of data, the analysis relies on the WER as the most common automated metric, which is a limited representation of ASR quality.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationreasoning

    Even though ASR might meet accuracy requirements for caption users for English, it might fail to meet them for other languages and outside narrowly defined scenarios, which is a real problem for accessibility of events.

    “Even though ASR might meet the accuracy requirements for caption users for English, it might fail to meet them for other languages and outside of narrowly deined scenarios, which is a real problem for the accessibility of events.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationreasoning

    These words might be fundamental for understanding the content and might consequently make the transcript more accessible.

    “Even though adding the vocabulary did not signiicantly decrease the overall WER, these words might be fundamental for understanding the content and might consequently make the transcript more accessible.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    To minimise the effects of audio processing that vendors might use, all samples were converted to a standard audio format and the volume was normalised.

    “To minimise the efects of audio processing that vendors might use, we converted all samples to a standard audio format and normalised the volume.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Interpretationreasoning

    The confidence values merely seem to represent the probabilities within an ASR-model, and not the actual correctness.

    “The conidence values merely seem to represent the probabilities within an ASR-model, and not the actual correctness.”
    Quote in the paperSubstantial claim
142 of 142
  • The paper relies on this without support.

    The eleven ASR services and higher education lecture recordings are representative of common ASR services and real-world use for DHH captioning.

    “We measured the performance of eleven common ASR services with recordings of Higher Education lectures.”
  • The paper relies on this without support.

    High accuracy is necessary for captions to be accessible.

    “transcription needs high levels of accuracy to be accessible.”
  • The paper relies on this without support.

    AI is good at keeping up with the speed of speech and creates almost verbatim transcripts.

    “AI is good at keeping up with the speed of speech, and creates almost verbatim transcripts.”
  • The paper relies on this without support.

    The amount of words in an ASR-generated transcript is almost identical to the amount of words spoken.

    “The amount of words in an ASR-generated transcript is almost identical to the amount of words spoken.”
  • The paper relies on this without support.

    AI can produce confusing words or sentences, by mistaking homonyms or hallucinating text.

    “But AI can produce confusing words or sentences, by mistaking homonyms or hallucinating text.”
  • The paper relies on this without support.

    The speed of an ASR system is a critical factor for evaluation.

    “The speed of an ASR-system is another critical factor.”
  • The paper relies on this without support.

    Volatile intermediate transcripts result in many text changes, which creates a negative user experience.

    “Volatile intermediate transcripts result in many text changes, which creates a negative user experience.”
  • The paper relies on this without support.

    The quality and amount of training data is the major factor influencing the performance of an ASR system.

    “But besides technical improvements in speciic areas and the evolution of machine learning in general, the quality and amount of training data is the major factor inluencing the performance of an ASR system.”
  • The paper relies on this without support.

    Using more high-quality training data increases the general accuracy of an ASR system.

    “Using more hiqh-quality training data increases the general accuracy of an ASR system.”
  • The paper relies on this without support.

    Research in speech recognition typically uses the WER to measure the accuracy of ASR systems.

    “Research in speech recognition typically uses the WER to measure the accuracy of ASR systems.”
  • The paper relies on this without support.

    AI-based metrics have the potential to better align with human judgement compared to WER.

    “AI based metrics have the potential to better align with human judgement compared”
  • The paper relies on this without support.

    AI-based metrics bear the risk of a bias related to their training data.

    “they also bear the risk of a bias related to their training data.”
  • The paper relies on this without support.

    ACE is trained on conversational speech.

    “ACE for example is trained on conversational speech”
  • The paper relies on this without support.

    Qualitative measures like those in the NER-model are subjective and hard to obtain on large datasets.

    “A drawback of the NER-model is that qualitative measures are subjective and hard to obtain on large datasets”
  • The paper relies on this without support.

    To reduce the impact of formatting differences, it is common to pre-process transcripts before the calculation of the WER.

    “To reduce the impact of these formatting diferences, it is common to pre-process transcripts before the calculation of the WER.”
  • The paper relies on this without support.

    Errors from capitalisation or grammatical cases are more common in languages other than English.

    “Errors from capitalisation or grammatical cases are more common in languages other than English”
  • The paper relies on this without support.

    There is no universal metric yet for measuring the stability of partial results in streaming ASR.

    “There is no universal metric yet, but Shangguan et al. [2020] propose to measure the stability as an unstable partial word ratio (UPWR) and Baumann et al. [2009] suggest an Incremental WER.”
  • The paper relies on this without support.

    There is a high demand for affordable and scalable transcription of lectures, talks and other learning formats in Higher Education.

    “We chose Higher Education as our use case as there is a high demand for afordable and scalable transcription of lectures, talks and other learning formats.”
  • The paper relies on this without support.

    Higher Education institutions are required to offer equal access to all students, and transcription of lectures is essential for that, benefiting DHH students, language learners, and remote students.

    “Higher Education institutions are required to ofer equal access to all students, and the transcription of lectures is an essential part of that, beneiting not only DHH students but also (second) language learners and students taking part remotely.”
  • The paper relies on this without support.

    Custom vocabulary words are weighted higher by the AI and prioritised during transcription, especially when the AI has similar probability values for multiple words.

    “These words will be weighted higher by the AI and prioritised during transcription, especially if the AI has similar probability values for multiple words.”
  • The paper relies on this without support.

    The duration an ASR service requires to process a file depends on multiple factors, like the complexity of the ASR pipeline, the model size and mainly the computing power provided by the vendor.

    “The duration an ASR service requires to process a ile depends on multiple factors, like the complexity of the ASR pipeline, the model size and mainly the computing power that is provided by the vendor.”
  • The paper relies on this without support.

    If a confidence is 80%, the measured WER should be 20%.

    “80% conident, the measured WER should be 20%.”
  • The paper relies on this without support.

    An evaluation on LibriSpeech can reflect the general accuracy of an ASR-model, if it is not explicitly optimised for this dataset.

    “An evaluation on LibriSpeech can relect the general accuracy of an ASR-model, if it is not explicitly optimised for this dataset.”
  • The paper relies on this without support.

    It is common in speech recognition research to apply text normalisation to make the WER more reliable to formatting differences.

    “It is common in speech recognition research to apply text normalisation to make the WER more reliable to formatting diferences.”
  • The paper relies on this without support.

    ASR continues to improve and error rates decrease, making metrics based on a string edit distance more robust.

    “ASR continues to improve and error rates decrease, making metrics based on a string edit distance more robust.”
  • The paper relies on this without support.

    DHH individuals are confronted with less ideal scenarios in real life.

    “However, DHH individuals are confronted with less ideal scenarios in real life.”
  • The paper relies on this without support.

    In many situations, speakers may not be able to choose a particular or even pre-trained ASR system, as it will be determined by the meeting or presentation software.

    “In many situations, speakers may not be able to choose a particular or even pre-trained ASR system, as it will be determined by the meeting or presentation software.”
  • The paper relies on this without support.

    To achieve near real-time transcription, a low RTF is required to reduce the latency between audio and transcription results.

    “To achieve near real-time transcription, a low RTF is required to reduce the latency between audio and transcription results.”
  • The paper relies on this without support.

    Larger models generally take longer to process.

    “as larger models generally take longer to process.”
  • The paper relies on this without support.

    The WER is objective, unbiased, and commonly used as an evaluation metric in ASR research.

    “Primary because it is objective, unbiased, and commonly used as an evaluation metric in ASR research.”
  • The paper relies on this without support.

    ASR/automatic transcription is particularly useful for real-time events.

    “as ASR is particularly useful for real-time events”
    “As automatic transcription is particularly useful for real-time events”
  • The paper relies on this without support.

    AI is a rapidly changing area of research.

    “as AI is a rapidly changing area of research.”
  • The paper relies on this without support.

    The Google Search Engine identifies the most relevant vendors that provide an API for fully automated transcription of audio or video files.

    “We used the Google Search Engine to ind the most relevant vendors that provide an API for fully automated transcription of audio or video iles.”
33 of 33

Statistics that don’t add up

Each reported p-value recomputed from its test statistic and degrees of freedom.

  • Inconsistent p-value across alpha = .05: t (1438)=-1.646,p < .01

    Major

    The paper reports p < .01 here; recomputing from the test statistic and its degrees of freedom gives p = .100 (two-tailed). The two fall on opposite sides of alpha = .05. The check cannot tell whether the statistic or the p-value is the misprint.

    Reported p < .01 · recomputed p = .100

  • Inconsistent p-value across alpha = .05: t (2578)=-1.645,p < .01

    Major

    The paper reports p < .01 here; recomputing from the test statistic and its degrees of freedom gives p = .100 (two-tailed). The two fall on opposite sides of alpha = .05. The check cannot tell whether the statistic or the p-value is the misprint.

    Reported p < .01 · recomputed p = .100

  • Inconsistent p-value: t (1438)=-1.646,p = .640

    Minor

    The paper reports p = .64 here; recomputing from the test statistic and its degrees of freedom gives p = .100 (two-tailed). The check cannot tell whether the statistic or the p-value is the misprint.

    Reported p = .64 · recomputed p = .100

3 of 3

Statistics recomputed

Every reported test result, recomputed from its test statistic and degrees of freedom. A result shows as not adding up only once an independent check has confirmed it.

  • Doesn’t add upt(1438) = -1.646reported p < .01 · recomputed p = .100The two fall on opposite sides of .05

    “t (1438)=-1.646,p < .01”

  • Doesn’t add upt(2578) = -1.645reported p < .01 · recomputed p = .100The two fall on opposite sides of .05

    “t (2578)=-1.645,p < .01”

  • Doesn’t add upt(1438) = -1.646reported p = .64 · recomputed p = .100

    “t (1438)=-1.646,p = .640”

3 of 3

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Identical t-tests report conflicting p-values

    Major

    The vocabulary and streaming comparisons report the same t statistic and degrees of freedom, but one gives p=0.640 and the other p<0.01. Both p-values cannot be correct; the streaming result is used to support a significant performance gap.

1 of 1

Cites

Flagged first, then by citations

Research works printed but not linked: 5

  1. Alexei Baevski, Henry Zhou, Abdelrahman Mohamed, and Michael Auli. 2020. Wav2vec 2.0: A framework for self-supervised learning of speech representations. In Proceedings of the 34th International Conference on Neural Information Processing Systems (NIPS’20). Article 1044, 12 pages.
  2. Sheryl Ballenger. 2022. Access for deaf and hard of hearing individuals in informational and educational remote sessions. Assistive Technology Outcomes & Benefits 16, 2 (2022), 45–55.
  3. 10.5555/1620754.1620810 · DOI
  4. John Hughes. 2023. Introducing Ursa from Speechmatics. Speechmatics. https://www.speechmatics.com/ursa
  5. Jane W. S. W. Liu. 2000. Real-Time Systems . Prentice Hall PTR.

Cited by

Sorted by citations

Authors
Kuhn, K., Kersken, V., Reuter, B., Egger, N., & Zimmermann, G.
Affiliations
Stuttgart Media University (DE)
Venue
ACM Transactions on Accessible Computing
Published
2023-12-31
Volume
16
Issue
4
Pages
1-23
ISSN
  • 1936-7228 (ISSN-L)
  • 1936-7236
OpenAlex
W4389486806
Cited by
44
References
42
Citations by year
2026: 15 · 2025: 20 · 2024: 9
FWCI
3.84
Type
journal article
Language
en
Open access
Locations
  • ACM Transactions on Accessible Computing (publishedVersion, public-domain)
  • arXiv (Cornell University) (submittedVersion, cc-by)
  • arXiv (Cornell University) (cc-by)
Funders
SHUFFLE
Topics
  • Physical Sciences › Computer Science › Artificial Intelligence › Speech Recognition and Synthesis
  • Social Sciences › Arts and Humanities › Language and Linguistics › Subtitles and Audiovisual Media
  • Physical Sciences › Computer Science › Signal Processing › Speech and Audio Processing
Keywords
speech recognition, captioning, deaf and hard of hearing, accessibility, transcription accuracy, streaming ASR, language differences

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-20.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-20.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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