Cited by 0Artificial Intelligence in Healthcare and EducationMeta-analysis and systematic reviewsInformation Retrieval and Search Behavior

Retrieve-Then-Verify for Evaluating Evidence Support and Hallucination in Large Language Model–Generated Medical Information: Empirical Study

Open access
Liang, Zhaohui, Sheffield, Cynthia, Butera, Gisela, Antani, Sameer·2026·JMIR AI

Published version of a preprint

Abstract

Background: Despite high reported accuracy on clinical and evidence appraisal tasks, AI-generated medical information may lack explicit support from source documents. This creates challenges for digital health practitioners regarding transparency, auditability, and trust when AI systems are used for evidence synthesis, guideline development, and clinical knowledge management. Large language models (LLMs) can generate fluent and seemingly correct outputs, but existing evaluations often rely on agreement with human judgments and do not directly assess whether AI-generated content is grounded in underlying evidence. Objective: This study measures evidence support and hallucination in AI-generated medical information by assessing the extent to which LLM-generated risk-of-bias assessments are supported by source clinical trial reports. Methods: We evaluated 3 LLMs (GPT-5, OpenAI o3-mini, and GPT-3.5) on risk-of-bias (RoB 2) assessment using all 97 randomized controlled trials for which the source Cochrane systematic review provided complete human RoB 2 annotations and full-text reports were accessible, constituting the complete reference set. No train-validation split was applied; all 97 studies were used for evaluation. Model outputs were constrained to structured RoB 2 signaling questions and domain-level judgments. For each generated claim, relevant text passages were retrieved from trial reports using the Okapi BM25 (Best Matching 25) algorithm. A verification step assigned evidence verdicts (supported, contradicted, not found, or out of scope) with verbatim quotations. We quantified evidence support rates and conservative and strict hallucination rates. Task performance was evaluated using exact and binary accuracy, sensitivity, specificity, F1-score, Youden J, and agreement with human reviewers using Cohen κ and Fleiss κ. Results: Binary accuracy of AI-generated risk-of-bias judgments was high across domains (90%-98%), whereas exact accuracy was substantially lower (42%-71%), reflecting frequent disagreements in severity classification despite correct directional classification. GPT-5 achieved the strongest overall performance, including perfect binary accuracy for overall risk-of-bias conclusions and the highest agreement with human reviewers (quadratic κ up to 0.81). However, evidence support rates across models ranged from only 60% to 65%, with conservative hallucination rates of 34%-37%. GPT-5 showed the highest mean evidence support (64.3%) and the lowest strict hallucination rate (35.7%). Mean top-1 BM25 retrieval scores were similar across models (approximately 30-31), suggesting that differences in hallucination were not primarily attributable to differences in retrieval strength. Conclusions: AI-generated medical information can achieve high decision-level accuracy while still lacking documentary support in a substantial proportion of outputs. Measuring evidence support and hallucination reveals important limitations that are not captured by agreement metrics alone. Retrieval-based evidence verification provides a reproducible and transparent approach for evaluating the reliability of AI-generated medical information, with direct relevance to digital health practice, evidence-based medicine, and medical informatics.

AI snapshot

Written from the paper’s full text.

TL;DR

This empirical study introduces a retrieve-then-verify (RtV) framework to measure whether LLM-generated medical claims are supported by source documents, using Cochrane RoB 2 assessment across 97 randomized controlled trials. It finds that high decision-level accuracy and human agreement can coexist with substantial lack of documentary support, with evidence support only 60%-65% and conservative hallucination rates of 34%-37%.

Key findings

  • Binary accuracy of AI-generated RoB judgments was high across domains (90%-98%), but exact accuracy was much lower (42%-71%), showing frequent severity-classification disagreements despite correct directional judgments.
  • Evidence support rates ranged from only 60% to 65% across models; conservative hallucination rates were 34%-37%, and GPT-5 had the highest mean evidence support (64.3%) and lowest strict hallucination rate (35.7%).
  • The accuracy-support gap ranged from 11% to 37% across domains and models, exceeding 30% in domains 2 and 5 for all models and exceeding 35% for the overall RoB conclusion.
  • Mean top-1 BM25 retrieval scores were similar across models (approximately 30-31), suggesting hallucination differences were not primarily due to retrieval strength; sensitivity analyses showed evidence support increased with larger top-k retrieval depth (k=1, 3, 5).

Methods

  • Retrospective evaluation using 97 randomized controlled trials from a 2023 Cochrane systematic review on mental health and well-being interventions, restricted to studies with complete RoB 2 data and accessible full-text PDFs; no train-validation split was applied.
  • Three LLMs (GPT-5, OpenAI o3-mini, GPT-3.5 Turbo) generated structured RoB 2 signaling-question and domain-level judgments via schema-constrained prompts; outputs were compared with human RoB 2 annotations using exact and binary accuracy, sensitivity, specificity, F1-score, Youden J, Cohen κ, and Fleiss κ.
  • For each generated claim, full-text reports were chunked (1400 characters, 200-character overlap) and retrieved with Okapi BM25 (top-k default 5); a constrained GPT-5 judge assigned verdicts of supported, contradicted, not found, or out of scope with verbatim quotations, yielding evidence support and conservative/strict hallucination rates. Embedding-based semantic similarity was used as a grounding diagnostic.

Limitations

  • Stated: BM25 lexical matching may miss paraphrased or implicitly stated evidence; PDF extraction quality, chunking strategy, and top-k selection may affect retrieval; verification relied on a single LLM judge; the evaluation used one Cochrane review of 97 RCTs in mental health and well-being, limiting generalizability; RoB assessment is subject to variable reporting quality and interreviewer subjectivity; generator reasoning depth was only partially examined; poor-quality PDFs may elevate hallucination rates.
  • Stated: prompt specifications were not validated on a separate held-out prompt development dataset.
  • Evident from the text: the same model family (GPT-5) served as both one of the evaluated generators and the verification judge, which could introduce shared-model bias in verdicts; the study reports no multijudge adjudication or cross-domain validation.

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

Integrity signals

Registry

Crossref · 10.2196/93761

Cites

28 of 28 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

44 of 49 cited sources checked · 25 supported · 2 flagged · accuracy not yet measured

  • Premisecitation

    LLMs can produce hallucinations, defined as generated outputs that are not supported by source materials.

    “A growing body of literature indicates that LLMs can produce hallucinations, defined here as generated outputs that are not supported by source materials, raising concerns regarding information quality and safety in health care applications [7-12].”
    Quote in the paperSubstantial claim6 of 6 sources checked
    • cites [7] source
    • cites [8] source
    • cites [9] source
    • cites [10] source
    • cites [11] source
    • cites [12] source

      The “Multimodal Hallucination” section defines hallucination as an MLLM response inconsistent with image content. This supports the core idea of output not grounded in its input, but the source does not establish the broader definition for LLMs generally or for source materials beyond images. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
  • Premisecitation

    Hallucination risks have been documented in acceptance or elaboration of fabricated clinical details embedded in prompts during clinical decision support.

    “acceptance or elaboration of fabricated clinical details embedded in prompts during clinical decision support [11]”
    Quote in the paperNot a substantial claim1 of 1 sources checked
  • Premisecitation

    AI-generated medical information may lack explicit support from source documents.

    “AI-generated medical information may lack explicit support from source documents.”
    Quote in the paperSubstantial claim6 of 6 sources checked
    • cites [7] source
    • cites [8] source
    • cites [9] source

      The Methods (Systematic Review on LLMs: Paper Retrieval; page unavailable) describe AI-generated references that could be “unsupported by the available literature,” and the Discussion (Principal Findings; page unavailable) reports hallucinated references in systematic reviews. This supports the possibility of unsupported AI-generated references, but the study does not assess whether medical information or claims are explicitly supported by source documents. (LLM, conf=0.83)

      Experimental — accuracy not yet measured
    • cites [10] source

      The Introduction’s ‘Advent of Generative AI—Large Language Models in Health Care’ section says LLMs may generate plausible but incorrect content. It does not address whether AI-generated medical information is explicitly supported by source documents; searches for source-document support and grounding found no passage on that point. Page numbers were not available in our copy. (LLM, conf=0.70)

      Experimental — accuracy not yet measured
    • cites [11] source
    • cites [12] source

      The “Multimodal Hallucination” section (page unavailable) says model-generated responses can be inconsistent with image content, supporting the general concern that AI output may be ungrounded. The “Scenario/task extension” section discusses medical image question answering, but the survey does not connect its hallucination discussion to medical information or to explicit support from source documents. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
  • Premisecitation

    Hallucination risks have been documented in fabricated or inaccurate references in systematic reviews.

    “including fabricated or inaccurate references in systematic reviews [7,9]”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [7] source

      The Introduction reports that AI chatbots generated citations that were fabricated or contained falsified bibliographic data. The paper does not place those references in systematic reviews; its Discussion describes reference hallucinations across chatbot outputs more generally. No page numbers are available in our copy. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [9] source
  • Premisecitation

    Hallucination risks have been documented in unsupported statements in clinical text summarization.

    “unsupported statements in clinical text summarization [8]”
    Quote in the paperSubstantial claim1 of 1 sources checked
  • Classified as probably not a substantial claim. 33
  • May combine two claims. 38
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Rose et al found moderate to substantial interrater agreement between ChatGPT-4o and human reviewers across Cochrane RoB review domains.

    “For example, Lai et al [18,27] demonstrated that LLMs can perform RoB assessments at a level comparable to trained reviewers in structured appraisal tasks, and Rose et al [25,26] found moderate to substantial interrater agreement between ChatGPT-4o and human reviewers across Cochrane RoB review domains.”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [25] source

      The Abstract (Results) describes agreement as an outcome the authors will report, not a finding. The Methods (Outcomes) explicitly says they will not assess agreement across Cochrane RoB domains, instead focusing on overall risk of bias. No page numbers are provided in our copy. (LLM, conf=0.90)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
    • cites [26] source

      Table 4 reports human–ChatGPT-4o agreement of 50.7% for overall RoB and 78.7% for RoB due to randomization. But its Cohen’s κ values are 0.215 (classified as fair by the paper’s criteria) and 0.537 (moderate), not moderate to substantial. The Discussion’s Strengths and Limitations section explicitly says the study did not assess other domains, so the claim overextends the finding across Cochrane RoB domains. (LLM, conf=0.91)

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

    Premisecitation

    Recent studies have reported promising agreement between LLMs and human reviewers for RoB assessment.

    “Recent studies have examined the ability of LLMs to assist with RoB assessment and have reported promising agreement with human reviewers [18,24-27].”
    Quote in the paperNot a substantial claim4 of 5 sources checked
    • cites [18] source
    • cites [24] source
    • cites [25] source

      The Abstract Conclusions (page unavailable) say the proposed study is likely to provide the first evidence of agreement between human and LLM risk-of-bias assessments. The Background (page unavailable) says the authors were unaware of research assessing agreement in overall risk-of-bias judgments. This protocol therefore does not report the promising agreement attributed to it. (LLM, conf=0.89)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
    • cites [26] source
    • cites [27] source
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Recent studies have explored the use of LLMs to assist with evidence appraisal tasks, including RoB assessment, and have reported promising agreement with human judgments.

    “Recent studies have explored the use of LLMs to assist with evidence appraisal tasks, including RoB assessment, and have reported promising agreement with human judgments [18].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
  • May combine two claims.

    Premisecitation

    Human RoB assessments in the source Cochrane review were performed independently by 2 reviewers using the RoB 2 tool, with discrepancies resolved through consensus discussion.

    “In accordance with standard Cochrane methodology, RoB assessments in the source review were performed independently by 2 reviewers using the RoB 2 tool, with discrepancies resolved through consensus discussion; full reviewer details are reported in the source review [19].”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [19] source

      The Methods (Data collection and analysis) state that two review authors (EP and CC) independently assessed risk of bias using the Cochrane Risk of Bias 2 tool. They resolved disagreements by discussion or consultation with a third review author, so the claim's description of resolution solely through consensus discussion omits an alternative the source reports. (LLM, conf=0.85)

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

    Premisecitation

    LLMs have demonstrated strong performance across a wide range of biomedical knowledge and reasoning tasks.

    “LLMs have demonstrated strong performance across a wide range of biomedical knowledge and reasoning tasks, accelerating their adoption in health care workflows [1-6].”
    Quote in the paperNot a substantial claim5 of 6 sources checked
    • cites [1] source
    • cites [2] source

      The Results (Emerging Trends; page unavailable) describe strong results on medical question answering and several biomedical NLP tasks, supporting examples of performance across different tasks. The Discussion (Prompt Engineering Techniques Effectiveness in Medical Research; page unavailable) cautions that results are not systematically in favor of LLM-based methods, so the unqualified claim of strong performance across a wide range overstates the review. The cited passages also do not establish that performance accelerated adoption in health care workflows. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [3] source

      The Discussion reports strong performance on theoretical, clinical, and integrated questions in a bilingual nuclear medicine exam, but the Conclusion also reports 0% accuracy on medical legal regulation questions. This supports performance on several biomedical knowledge and reasoning tasks, not a wide range of tasks generally; the cited passages also do not establish accelerated adoption in health care workflows. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [4] source

      The Abstract and Discussion report strong Med-PaLM 2 performance across medical knowledge benchmarks, long-form answers, and bedside consultation questions. The Discussion says validation in real-world workflows remains future work; it does not establish that this performance has accelerated adoption in health care workflows. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites [5] source
    • cites [6] source

      The Introduction (page unavailable) describes LLMs as powerful NLP tools across different tasks, and the Conclusion reports promising results for literature-review automation. The paper does not establish strong performance across a wide range of biomedical knowledge and reasoning tasks or show that such performance accelerated adoption in health care workflows. (LLM, conf=0.83)

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

    Premisecitation

    Conceptual and sociotechnical analyses suggest that naive reliance on AI-generated medical information may amplify automation bias, erode professional expertise, and reinforce self-referential learning loops in digital health systems.

    “Conceptual and sociotechnical analyses further suggest that naive reliance on AI-generated medical information may amplify automation bias, erode professional expertise, and reinforce self-referential learning loops in digital health systems [10].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The revised RoB 2 tool introduced outcome-specific domains, signaling questions, and explicit decision rules to improve consistency.

    “Although the revised RoB 2 tool introduced outcome-specific domains, signaling questions, and explicit decision rules to improve consistency [17]”
    Quote in the paperNot a substantial claim1 of 1 sources checked
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Reviewers were systematic review specialists with expertise in global mental health interventions.

    “Reviewers were systematic review specialists with expertise in global mental health interventions; their institutional affiliations and authorship details are listed in the source review [19].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [19] source

      The Methods > Data collection and analysis section identifies review authors conducting systematic screening, risk-of-bias assessment, and GRADE assessment for this review of mental-health interventions in low- and middle-income countries. This supports describing them as reviewers working in that field. The available copy does not show their institutional affiliations or establish that all were systematic review specialists; its end may be missing. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
  • May combine two claims.

    Premisecitation

    RoB assessment has long been recognized as labor intensive, variably reproducible, and prone to misapplication in specific domains such as selective reporting.

    “However, RoB assessment has long been recognized as labor intensive, variably reproducible, and prone to misapplication in specific domains such as selective reporting [14-16].”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [14] source
    • cites [15] source

      The Results (Table 2; page unavailable in our copy) show poor agreement between reviewer groups for selective reporting (κ = 0.13), and the Discussion says RoB assessments may not be reproducible across groups. The paper describes intensive reviewer training, but does not establish that RoB assessment itself is labor intensive. Poor agreement in the selective-reporting domain does not, on its own, establish misapplication. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [16] source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The Cochrane risk-of-bias (RoB) assessment tool formalized a structured, domain-based approach to judgments anchored in trial methodology rather than undifferentiated quality scores.

    “Within systematic reviews, the Cochrane risk-of-bias (RoB) assessment tool formalized a structured, domain-based approach to judgments anchored in trial methodology rather than undifferentiated quality scores [13].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
  • May combine two claims.

    Premisecitation

    Prior work has found hallucinations in several relevant domains, including fabricated or inaccurate references in systematic reviews, unsupported claims in clinical text summarization, and adversarial exploitation of false clinical details in decision support systems.

    “Prior work has found hallucinations in several relevant domains, including fabricated or inaccurate references in systematic reviews [7,9], unsupported claims in clinical text summarization [8], and adversarial exploitation of false clinical details in decision support systems [11].”
    Quote in the paperNot a substantial claim4 of 4 sources checked
    • cites [7] source

      The Results report inaccurate or hallucinated references generated by medical AI chatbots, supporting the reference-error portion of the claim. The Methods (Medical Prompts) say the chatbots were asked about medical topics and clinical scenarios, not to produce systematic reviews; this source does not establish the systematic-review setting. The other two domains in the citing sentence are attached to different citations. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites [9] source
    • cites [8] source
    • cites [11] source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Lai et al demonstrated that LLMs can perform RoB assessments at a level comparable to trained reviewers in structured appraisal tasks.

    “For example, Lai et al [18,27] demonstrated that LLMs can perform RoB assessments at a level comparable to trained reviewers in structured appraisal tasks, and Rose et al [25,26] found moderate to substantial interrater agreement between ChatGPT-4o and human reviewers across Cochrane RoB review domains.”
    Quote in the paperNot a substantial claim2 of 2 sources checked
  • May combine two claims.

    Findingown data

    GPT-5 attained the highest exact accuracy in most RoB 2 assessment domains, including 0.64 in domain 1, 0.54-0.71 in domains 2 and 3, and 0.42-0.45 in domains 4 and 5.

    “and attained the highest exact accuracy in most RoB 2 assessment domains, including 0.64 in domain 1, 0.54-0.71 in domains 2 and 3, and 0.42-0.45 in domains 4 and 5.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    GPT-3.5 showed modestly lower evidence support and higher hallucination rates across all 3 measures.

    “GPT-3.5 showed modestly lower evidence support and higher hallucination rates across all 3 measures.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    Evidence support rates increased substantially and consistently with larger k across all 8 topics, while conservative and strict hallucination rates decreased correspondingly.

    “As shown in Figure 4, evidence support rates increased substantially and consistently with larger k across all 8 topics, while conservative and strict hallucination rates decreased correspondingly.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    RtV required end-to-end runtimes of 50-158 seconds per study, depending on model choice, and the computational requirements were modest.

    “It required end-to-end runtimes of 50-158 seconds per study, depending on model choice, and the computational requirements were modest.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    OpenAI o3-mini closely tracked GPT-5 on binary accuracy but consistently showed lower exact accuracy.

    “OpenAI o3-mini closely tracked GPT-5 on binary accuracy but consistently showed lower exact accuracy”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingreasoning

    AI-generated RoB judgments frequently agreed with human judgments while simultaneously lacking evidence grounding in the original trial reports.

    “AI-generated RoB judgments frequently agreed with human judgments while simultaneously lacking evidence grounding in the original trial reports.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    The included trials were published between 1996 and 2022.

    “The included trials were published between 1996 and 2022.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data

    The reasoning-capable judge assigned higher evidence support rates across most topics and produced more decisive conservative hallucination classifications.

    “The reasoning-capable judge assigned higher evidence support rates across most topics and produced more decisive conservative hallucination classifications.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    Lower reasoning depth in the generator model reduced both evidence support (65.5% to 55.9% pooled) and binary accuracy (89.5% to 77.7% pooled), without a comparable change in retrieval scores.

    “Lower reasoning depth in the generator model reduced both evidence support (65.5% to 55.9% pooled) and binary accuracy (89.5% to 77.7% pooled), without a comparable change in retrieval scores.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    Across domains, quadratic κ values consistently exceeded linear κ values, indicating that most disagreements involved adjacent categories on the ordinal RoB 2 scale rather than large category gaps.

    “Across domains, quadratic κ values consistently exceeded linear κ values, indicating that most disagreements involved adjacent categories on the ordinal RoB 2 scale rather than large category gaps.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data

    For the overall RoB conclusion, gaps exceeded 35% across models, indicating that many apparently correct judgments were not explicitly supported by the trial reports.

    “For the overall RoB conclusion, gaps exceeded 35% across models, indicating that many apparently correct judgments were not explicitly supported by the trial reports.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    GPT-5 achieved perfect performance on the overall RoB conclusion, with accuracy, sensitivity, specificity, F1-score, and Youden J all of 1.00.

    “It achieved perfect performance on the overall RoB conclusion, with accuracy, sensitivity, specificity, F1-score, and Youden J all of 1.00”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    Internal consistency across models was strong in domain 1 (Fleiss κ=0.83) and domain 2 (Fleiss κ=0.86), and moderate in domains 3-5 (Fleiss κ of approximately 0.49-0.60) and for the overall RoB conclusion (Fleiss κ=0.51).

    “Internal consistency across models was strong in domain 1 (Fleiss κ=0.83) and domain 2 (Fleiss κ=0.86), and moderate in domains 3-5 (Fleiss κ of approximately 0.49-0.60) and for the overall RoB conclusion (Fleiss κ=0.51).”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    Mean support rate across RoB 2 domains was higher in domain 1 (approximately 0.78-0.80) and lower in domain 3 (approximately 0.56-0.59) across models.

    “Radar plots of mean support rate across RoB 2 domains (Figure 3C) showed higher evidence support in domain 1 (approximately 0.78-0.80) and lower support in domain 3 (approximately 0.56-0.59) across models, potentially reflecting differences in reporting clarity and methodological complexity.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Assessments covered 7 outcome categories: diagnosis of mental disorders, quality of life, adverse events, psychological functioning and impairment, depressive symptoms, anxiety symptoms, and distress or posttraumatic stress disorder symptoms.

    “Assessments covered 7 outcome categories: diagnosis of mental disorders, quality of life, adverse events, psychological functioning and impairment, depressive symptoms, anxiety symptoms, and distress or posttraumatic stress disorder symptoms.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    Hallucination reflects a general and high-stakes failure mode of AI-generated medical information in digital health systems, where plausible statements lack documentary support but may nonetheless influence downstream decisions.

    “In this sense, hallucination reflects a general and high-stakes failure mode of AI-generated medical information in digital health systems, where plausible statements lack documentary support but may nonetheless influence downstream decisions.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Most evaluations of hallucination in AI-generated health information rely on indirect measures such as agreement with human judgments, task-level accuracy, or expert preference ratings.

    “Despite growing recognition of these risks, most evaluations of hallucination in AI-generated health information rely on indirect measures such as agreement with human judgments, task-level accuracy, or expert preference ratings.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    The proposed approach provides reproducible, source-linked quality metrics that are directly relevant to digital health applications.

    “The proposed approach provides reproducible, source-linked quality metrics that are directly relevant to digital health applications.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    The proposed evaluation approach is model-agnostic and task-general.

    “While RoB assessment provides a concrete and well-defined test case, the proposed evaluation approach is model-agnostic and task-general.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Generalizability to other clinical specialties, review types, or evidence appraisal frameworks has not been established.

    “Generalizability to other clinical specialties, review types, or evidence appraisal frameworks has not been established and represents an important direction for future work.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationown data

    AI-generated medical information can achieve high decision-level accuracy while a substantial proportion of outputs remain unsupported by the source documents underlying the judgments.

    “This study reveals that AI-generated medical information can achieve high decision-level accuracy while a substantial proportion of outputs remain unsupported by the source documents underlying the judgments.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationown data

    The domain-level pattern potentially reflects differences in reporting clarity and methodological complexity.

    “Radar plots of mean support rate across RoB 2 domains (Figure 3C) showed higher evidence support in domain 1 (approximately 0.78-0.80) and lower support in domain 3 (approximately 0.56-0.59) across models, potentially reflecting differences in reporting clarity and methodological complexity.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    The embedding-based semantic grounding diagnostic directly evaluates whether the model's stated rationale is semantically close to the retrieved trial text, including when the supporting evidence is paraphrased rather than lexically matched.

    “This directly evaluates whether the model’s stated rationale is semantically close to the retrieved trial text, including when the supporting evidence is paraphrased rather than lexically matched.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Premisereasoning

    Agreement metrics summarize alignment with human judgments but do not assess whether model rationales are supported by the source documents.

    “While these metrics summarize alignment with human judgments, they do not assess whether model rationales are supported by the source documents.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Prompt adequacy was verified through iterative review against the instrument's signaling questions and decision rules before full-scale application across all 97 studies.

    “Prompt adequacy was verified through iterative review against the instrument’s signaling questions and decision rules before full-scale application across all 97 studies.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Study design and conductnone given

    The RtV procedure operationalizes hallucination assessment by explicitly separating information retrieval from claim verification.

    “The RtV procedure operationalizes hallucination assessment by explicitly separating information retrieval from claim verification.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductreasoning

    The constrained design minimized variability associated with free-text generation and ensured consistency across models and studies.

    “This constrained design minimized variability associated with free-text generation and ensured consistency across models and studies.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    This design enables a distinction between failures of evidence access and failures of model reasoning.

    “This design enables a distinction between failures of evidence access and failures of model reasoning.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Prompt specifications were developed based on the structure and decision logic of the Cochrane RoB 2 instrument and were not validated on a separate held-out prompt development dataset.

    “Prompt specifications were developed based on the structure and decision logic of the Cochrane RoB 2 instrument [20] and were not validated on a separate held-out prompt development dataset.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [20] RoB 2: revised Cochrane risk-of-bias tool for randomized trialsCochrane20252026-05-04https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials

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

  • May combine two claims.

    Interpretationown data

    The divergence among binary accuracy, exact accuracy, and evidence support highlights a key limitation of agreement-based evaluation and underscores the importance of assessing whether AI-generated judgments are grounded in source documents.

    “The divergence among binary accuracy, exact accuracy, and evidence support highlights a key limitation of agreement-based evaluation and underscores the importance of assessing whether AI-generated judgments are grounded in source documents.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Verification relied on a single LLM judge, which may introduce systematic bias in borderline or ambiguous cases.

    “Verification relied on a single LLM judge, which may introduce systematic bias in borderline or ambiguous cases; multijudge adjudication or ensemble verification approaches could reduce this risk, albeit at the cost of increased runtime.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductreasoning

    The structured output enabled consistent mapping to analytic variables, automated calculation of performance metrics, and traceability for adjudication.

    “This structure enabled consistent mapping to analytic variables, automated calculation of performance metrics, and traceability for adjudication.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Study design and conductown data

    Each verification response included a verbatim quotation drawn from the retrieved trial text that grounds the judgment, making the evidentiary basis for each item-level decision directly traceable without requiring downstream re-derivation.

    “Each response also included the verdict label, a verbatim quotation drawn from the retrieved trial text that grounds the judgment, and a 1-sentence rationale, making the evidentiary basis for each item-level decision directly traceable without requiring downstream re-derivation.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The constrained judge LLM (GPT-5) verdicts accurately classify whether a generated claim is supported, contradicted, not found, or out of scope.
  • May combine two claims.

    Interpretationown data

    Agreement and evidence grounding capture different aspects of model reliability, and high agreement does not imply that generated claims are traceable to source documents.

    “Our study addresses this gap by demonstrating that agreement and evidence grounding capture different aspects of model reliability, and that high agreement does not imply that generated claims are traceable to source documents.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationnone given

    Higher semantic similarity indicates stronger semantic grounding of the explanation in the retrieved evidence, whereas low similarity across retrieved snippets indicates weak grounding and potential hallucination risk.

    “Higher semantic similarity indicates stronger semantic grounding of the explanation in the retrieved evidence, whereas low similarity across retrieved snippets indicates weak grounding and potential hallucination risk.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The top-k BM25 retrieved passages contain all evidence needed to verify each claim.
  • May combine two claims.

    Interpretationown data

    GPT-5 offered the most favorable balance between evidence support and hallucination control, with OpenAI o3-mini remaining closely comparable and GPT-3.5 exhibiting the highest tendency toward unsupported claims.

    “In summary, GPT-5 offered the most favorable balance between evidence support and hallucination control, with OpenAI o3-mini remaining closely comparable and GPT-3.5 exhibiting the highest tendency toward unsupported claims.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Retrieval parameters were applied consistently across all 97 studies and all 3 LLMs.

    “These parameters were applied consistently across all 97 studies and all 3 LLMs.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Interpretationreasoning

    The resulting evidence support and hallucination metrics complement conventional accuracy and agreement measures by directly assessing whether AI-generated medical information is grounded in source documents.

    “The resulting evidence support and hallucination metrics complement conventional accuracy and agreement measures by directly assessing whether AI-generated medical information is grounded in source documents.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationown data

    This pattern suggests high convergence in domains governed by explicit methodological criteria and greater divergence in domains requiring more nuanced interpretation.

    “This pattern suggests high convergence in domains governed by explicit methodological criteria and greater divergence in domains requiring more nuanced interpretation.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Premisereasoning

    Prior studies mainly focus on decision-level agreement and do not assess whether model outputs are grounded in the trial reports used as source evidence.

    “However, these studies mainly focus on decision-level agreement and do not assess whether model outputs are grounded in the trial reports used as source evidence.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning

    The chunk size of 1400 characters with 200-character overlap was selected to balance sufficient local context per passage with retrieval precision, and the overlap helped ensure that claims spanning chunk boundaries were not missed.

    “The chunk size was selected to balance sufficient local context per passage with retrieval precision; the 200-character overlap helped ensure that claims spanning chunk boundaries were not missed.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationown data

    Both retrieval depth and judge model reasoning capacity are important determinants of RtV evaluation outcomes.

    “The sensitivity analyses further demonstrated that both retrieval depth and judge model reasoning capacity are important determinants of RtV evaluation outcomes, and that an appropriate top-k configuration combined with a reasoning-capable judge may provide a robust design choice for this framework.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationreasoning

    Retrieval-based evidence verification provides a reproducible and transparent approach for evaluating the reliability of AI-generated medical information, with direct relevance to digital health practice, evidence-based medicine, and medical informatics.

    “Retrieval-based evidence verification provides a reproducible and transparent approach for evaluating the reliability of AI-generated medical information, with direct relevance to digital health practice, evidence-based medicine, and medical informatics.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The constrained judge LLM (GPT-5) verdicts accurately classify whether a generated claim is supported, contradicted, not found, or out of scope.
    • Rests on an assumption: The top-k BM25 retrieved passages contain all evidence needed to verify each claim.
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    For a subset of unsupported verdicts, low similarity may partly reflect genuine underretrieval rather than paraphrasing alone, and these explanations cannot be fully disentangled using lexical and embedding diagnostics alone.

    “We acknowledge that, for a subset of unsupported verdicts, low similarity may partly reflect genuine underretrieval rather than paraphrasing alone, and these explanations cannot be fully disentangled using lexical and embedding diagnostics alone.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationown data

    Differences in hallucination rates were not primarily attributable to differences in retrieval strength and may instead reflect differences in reasoning and interpretation.

    “The consistency of BM25 retrieval scores across models suggests that differences in hallucination rates were not primarily attributable to differences in retrieval strength and may instead reflect differences in reasoning and interpretation.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationown data

    LLMs often identify the correct direction of risk but frequently do so without sufficient evidentiary support.

    “Together, these findings show that while LLMs often identify the correct direction of risk, they frequently do so without sufficient evidentiary support.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    This evaluation framework supports reproducible auditing, cross-model comparison, and systematic analysis of hallucination risk in AI-generated medical information for digital health systems.

    “This evaluation framework supports reproducible auditing, cross-model comparison, and systematic analysis of hallucination risk in AI-generated medical information for digital health systems.”
    Quote in the paperSubstantial claim
59 of 59
  • The paper relies on this without support.

    The constrained judge LLM (GPT-5) verdicts accurately classify whether a generated claim is supported, contradicted, not found, or out of scope.

    “Verification was performed by a constrained judge LLM (GPT-5). The judge received the trial identifier, question text, model output, explanation, and retrieved passages and returned structured JSON containing 1 of 4 verdicts: supported, contradicted, not found, or out of scope.”
  • The paper relies on this without support.

    The top-k BM25 retrieved passages contain all evidence needed to verify each claim.

    “BM25 was used to rank document chunks and return the top-k passages (default k=5).”
  • The paper relies on this without support.

    Human RoB assessments used as the reference standard are accurate.

    “Binary accuracy of AI-generated RoB judgments was high across all domains (90%-98%), whereas evidence support rates clustered at only 60%-65%.”
  • The paper relies on this without support.

    The RtV framework's verdicts (supported, contradicted, not found, out-of-scope) validly measure evidence support and hallucination.

    “To complement accuracy and agreement analyses, we evaluated evidence support and hallucination using the RtV metrics.”
  • The paper relies on this without support.

    BM25 top-1 score reflects retrieval strength or access to relevant evidence.

    “As BM25 scores reflect lexical relevance between queries and retrieved passages, these similar values suggest comparable access to potentially relevant evidence across models.”
  • The paper relies on this without support.

    Semantic similarity between the LLM's rationale and retrieved passages is a valid grounding diagnostic.

    “To complement BM25 lexical retrieval, we computed embedding-based semantic similarity between the LLM’s stated rationale and the retrieved passages as an additional grounding diagnostic (Multimedia Appendix 3).”
  • The paper relies on this without support.

    RoB assessment is a well-characterized use case for evaluating evidence grounding.

    “This study introduced an RtV framework to measure evidence support and hallucination in AI-generated medical information at the claim level, using RoB assessment as a concrete and well-characterized use case.”
7 of 7

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.

  • Consistentz = 20.14reported p < .001 · recomputed p < .001

    “z=20.14, p < .001”

1 of 1

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.

  • Seven listed outcome categories conflict with an eighth in Table 3

    Minor

    The methods list seven outcome categories, but Table 3 additionally reports "Social outcomes" as a topic for every model.

  • GPT-3.5 does not perform worse on both measures in every domain

    Minor

    Table 1 reports higher domain 2 exact and binary accuracy for GPT-3.5 (50.97% and 93.57%) than for OpenAI o3-mini (49.70% and 93.48%).

  • Quadratic κ does not always exceed linear κ

    Minor

    Table 2 shows the reverse in domain 4 for all three models; for example, GPT-5 has linear κ=0.31 and quadratic κ=0.29.

  • Exact accuracy range excludes reported values below 42%

    Minor

    The stated 42%-71% exact-accuracy range excludes Table 1 values, including GPT-3.5's 37.67% in domain 4. It also excludes GPT-5's 90.99% exact accuracy for the overall conclusion if that conclusion is included in the range.

  • Domain 5 gap does not exceed 30% for every model

    Minor

    The claim that domain 5 gaps exceeded 30% for all models conflicts with the 29.78% gap reported for OpenAI o3-mini.

5 of 5

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. 2026, NIH Policy Manual 3014: NIH Intramural Human Research Protection Program

Cited by

Still being checked.

Authors
Liang, Z., Sheffield, C., Butera, G., & Antani, S.
Affiliations
National Institutes of Health (US)
Corresponding author
Antani, Sameer
Venue
JMIR AI
Published
2026-09-16
Volume
5
Pages
e93761
ISSN
2817-1705 (ISSN-L)
OpenAlex
W7213397745
Cited by
0
References
27
FWCI
0.00
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • JMIR AI (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
Funders
  • U.S. Department of Health and Human Services
  • National Institutes of Health
Topics
  • Health Sciences › Medicine › Health Informatics › Artificial Intelligence in Healthcare and Education
  • Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
  • Physical Sciences › Computer Science › Information Systems › Information Retrieval and Search Behavior
Keywords
hallucinations, large language models, risk of bias assessment, RoB 2, clinical trial reports, BM25 retrieval, AI-generated medical information, GPT-5, GPT-3.5, evidence appraisal, auditability, trust in AI-generated content, human-AI agreement

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 2026-10-30.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-30.

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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