Cited by 715Statistical Methods in Clinical TrialsAdvanced Causal Inference TechniquesMeta-analysis and systematic reviews

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Intention-to-Treat Analysis: Implications for Quantitative and Qualitative Research

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NEWELL, DAVID J·1992·International Journal of Epidemiology

DOI 10.1093/ije/21.5.837

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Abstract

Newell D J (Department of Medical Statistics, University of Newcastle upon Tyne, UK). Intention-to-treat analysis: implications for quantitative and qualitative research. International Journal of Epidemiology 1992, 21: 837–841 Intention-to-treat analysis is an important aspect of randomized controlled trials of health care interventions. The concept is now widely accepted in theory, but not always implemented in practice. Failure to analyse by intention-to-treat can give misleading and indeed life-threatening interpretations. In some studies, a case is put for estimating the effect that would have been observed if all patients had received the allocated treatment. Situations where this is valid are rare, but an example is given of such an exceptional study. The relevance of the intention-to-treat concept is not always taken into account in qualitative research. Interviews with new mothers who delivered their babies at home in a hypothetical controlled trial of home versus hospital confinement would provide fascinating accounts of the pleasures of successful delivery at home. But by definition the interviews would exclude the hazard and drama of necessary transfers to hospital due to complications in late pregnancy and early labour. The intention-to-treat approach would avoid this bias.

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Schwartz D, Flamant R, LeUouch i. Clinical Trials. London: Academic Press, 1980.

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“Changing these groups by removing incomplete data or excluding drop-outs reduces this comparability (Newell, 1992), and is likely to lead to biassed results.”
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“Statistical analysis considering the intention to treat is generally viewed as a more conservative approach than including only those who completed the entire treatment (31).”
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“Newell 1992 Newell DJ. Intention-to-treat analysis: implications for quantitative and qualitative research.”
BackgroundMethod
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“Intentionto-treat analysis of trial outcomes is recommended precisely because not everyone in the intervention group will actually receive the intervention or receive it in the same way, and not everyone in the control group will be deprived of the intervention.(35) The term ‘controlled’ may lead to some confusion her…”
Background
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“Newell 1992 Newell DJ. Intention-to-treat analysis: implications for quantitative and qualitative research.”
BackgroundMethod
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“[0003–4932: (Print)] Newell 1992 Newell DJ. Intention-to-treat analysis: implications for quantitative and qualitative research.”
BackgroundMethod

Authors: NEWELL, D. J.
Affiliations: Newcastle University (GB)
Corresponding author: NEWELL, DAVID J
ORCID: NEWELL, DAVID J
Venue: International Journal of Epidemiology
Publisher: Oxford University Press (OUP)
Published: 1992
Volume: 21
Issue: 5
Pages: 837-841
ISSN: 0300-5771 (ISSN-L)
1464-3685
DOI: 10.1093/ije/21.5.837
OpenAlex: W2106051200
Cited by: 715
References: 6
Citations by year: 2026: 4 · 2025: 15 · 2024: 24 · 2023: 22 · 2022: 21 · 2021: 16 · 2020: 16 · 2019: 16 · 2018: 25 · 2017: 36 · 2016: 31 · 2015: 35 · 2014: 51 · 2013: 62 · 2012: 34
FWCI: 5.99
Type: journal article
Language: en
Open access: bronze
doi.org
Locations: International Journal of Epidemiology (publishedVersion)
PubMed (publishedVersion)
Topics: Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Clinical Trials
Physical Sciences › Mathematics › Statistics and Probability › Advanced Causal Inference Techniques
Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
Keywords: intention-to-treat analysis, randomized controlled trials, health interventions, qualitative research, home birth, hospital confinement, allocation bias, treatment effect estimation
MeSH terms: Data Interpretation, Statistical, Evaluation Studies as Topic, Humans, Patient Compliance, Random Allocation, Research Design, Therapeutics, Cohort Studies, Randomized Controlled Trials as Topic

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Intention-to-Treat Analysis: Implications for Quantitative and Qualitative Research

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