Analysis of decisions made in meta-analyses of depression screening and the risk of confirmation bias: A case study

Felicity A. Goodyear-Smith, Mieke L. Van Driel, Bruce Arroll, Chris Del Mar

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23 Citations (Scopus)
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Abstract

Background: Depression is common in primary care and clinicians are encouraged to screen their patients. Metaanalyses have evaluated the effectiveness of screening, but two author groups consistently reached completely opposite conclusions. Methods: We identified five systematic reviews on depression screening conducted between 2001 and 2009, three by Gilbody and colleagues and two by the United States Preventive Task Force. The two author groups consistently reached completely opposite conclusions. We analyzed two contemporaneous systematic reviews, applying a stepwise approach to unravel their methods. Decision points were identified, and discrepancies between systematic reviews authors justification of choices made were recorded. Results: Two systematic reviews each addressing three research questions included 26 randomized controlled trials with different combinations in each review. For the outcome depression screening resulting in treatment, both reviews undertook meta-analyses of imperfectly overlapping studies. Two in particular, pooled each by only one of the reviews, influenced the recommendations in opposite directions. Justification for inclusion or exclusion of studies was obtuse. Conclusion: Systematic reviews may be less objective than assumed. Based on this analysis of two meta-analyses we hypothesise that strongly held prior beliefs (confirmation bias) may have influenced inclusion and exclusion criteria of studies, and their interpretation. Authors should be required to declare a priori any strongly held prior beliefs within their hypotheses, before embarking on systematic reviews.

Original languageEnglish
Article number76
JournalBMC Medical Research Methodology
Volume12
DOIs
Publication statusPublished - 2012

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Decision Support Techniques
Meta-Analysis
Advisory Committees
Primary Health Care
Randomized Controlled Trials
Research
Therapeutics
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title = "Analysis of decisions made in meta-analyses of depression screening and the risk of confirmation bias: A case study",
abstract = "Background: Depression is common in primary care and clinicians are encouraged to screen their patients. Metaanalyses have evaluated the effectiveness of screening, but two author groups consistently reached completely opposite conclusions. Methods: We identified five systematic reviews on depression screening conducted between 2001 and 2009, three by Gilbody and colleagues and two by the United States Preventive Task Force. The two author groups consistently reached completely opposite conclusions. We analyzed two contemporaneous systematic reviews, applying a stepwise approach to unravel their methods. Decision points were identified, and discrepancies between systematic reviews authors justification of choices made were recorded. Results: Two systematic reviews each addressing three research questions included 26 randomized controlled trials with different combinations in each review. For the outcome depression screening resulting in treatment, both reviews undertook meta-analyses of imperfectly overlapping studies. Two in particular, pooled each by only one of the reviews, influenced the recommendations in opposite directions. Justification for inclusion or exclusion of studies was obtuse. Conclusion: Systematic reviews may be less objective than assumed. Based on this analysis of two meta-analyses we hypothesise that strongly held prior beliefs (confirmation bias) may have influenced inclusion and exclusion criteria of studies, and their interpretation. Authors should be required to declare a priori any strongly held prior beliefs within their hypotheses, before embarking on systematic reviews.",
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Analysis of decisions made in meta-analyses of depression screening and the risk of confirmation bias : A case study. / Goodyear-Smith, Felicity A.; Van Driel, Mieke L.; Arroll, Bruce; Del Mar, Chris.

In: BMC Medical Research Methodology, Vol. 12, 76, 2012.

Research output: Contribution to journalReview articleResearchpeer-review

TY - JOUR

T1 - Analysis of decisions made in meta-analyses of depression screening and the risk of confirmation bias

T2 - A case study

AU - Goodyear-Smith, Felicity A.

AU - Van Driel, Mieke L.

AU - Arroll, Bruce

AU - Del Mar, Chris

PY - 2012

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N2 - Background: Depression is common in primary care and clinicians are encouraged to screen their patients. Metaanalyses have evaluated the effectiveness of screening, but two author groups consistently reached completely opposite conclusions. Methods: We identified five systematic reviews on depression screening conducted between 2001 and 2009, three by Gilbody and colleagues and two by the United States Preventive Task Force. The two author groups consistently reached completely opposite conclusions. We analyzed two contemporaneous systematic reviews, applying a stepwise approach to unravel their methods. Decision points were identified, and discrepancies between systematic reviews authors justification of choices made were recorded. Results: Two systematic reviews each addressing three research questions included 26 randomized controlled trials with different combinations in each review. For the outcome depression screening resulting in treatment, both reviews undertook meta-analyses of imperfectly overlapping studies. Two in particular, pooled each by only one of the reviews, influenced the recommendations in opposite directions. Justification for inclusion or exclusion of studies was obtuse. Conclusion: Systematic reviews may be less objective than assumed. Based on this analysis of two meta-analyses we hypothesise that strongly held prior beliefs (confirmation bias) may have influenced inclusion and exclusion criteria of studies, and their interpretation. Authors should be required to declare a priori any strongly held prior beliefs within their hypotheses, before embarking on systematic reviews.

AB - Background: Depression is common in primary care and clinicians are encouraged to screen their patients. Metaanalyses have evaluated the effectiveness of screening, but two author groups consistently reached completely opposite conclusions. Methods: We identified five systematic reviews on depression screening conducted between 2001 and 2009, three by Gilbody and colleagues and two by the United States Preventive Task Force. The two author groups consistently reached completely opposite conclusions. We analyzed two contemporaneous systematic reviews, applying a stepwise approach to unravel their methods. Decision points were identified, and discrepancies between systematic reviews authors justification of choices made were recorded. Results: Two systematic reviews each addressing three research questions included 26 randomized controlled trials with different combinations in each review. For the outcome depression screening resulting in treatment, both reviews undertook meta-analyses of imperfectly overlapping studies. Two in particular, pooled each by only one of the reviews, influenced the recommendations in opposite directions. Justification for inclusion or exclusion of studies was obtuse. Conclusion: Systematic reviews may be less objective than assumed. Based on this analysis of two meta-analyses we hypothesise that strongly held prior beliefs (confirmation bias) may have influenced inclusion and exclusion criteria of studies, and their interpretation. Authors should be required to declare a priori any strongly held prior beliefs within their hypotheses, before embarking on systematic reviews.

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