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Systematic Reviews & Other Syntheses

Introduction

Risk of bias assessment of eligible studies is an integral component of conducting a systematic review and many other types of syntheses. 

Sometimes the terms critical appraisal and risk of bias are used interchangeably as a step in the synthesis process. However, the original conception of critical appraisal (as a step in practicing evidence-based medicine, for example) often goes beyond internal validity into assessment of external validity, generalizability, and even reporting quality [1]. International research collaborations such as Cochrane and JBI use the term “risk of bias” when referring to the assessment of the internal validity of studies included in quantitative syntheses, where bias is considered to be systematic error in the results of quantitative studies [1,2].

Risk of Bias and Critical Appraisal Tools

For animal studies: 

Other:

Bibliography

  1. Stone JC, Barker TH, Aromataris E, Ritskes-Hoitinga M, Sears K, Klugar M et al. From critical appraisal to risk of bias assessment: clarifying the terminology for study evaluation in JBI systematic reviews. JBI Evidence Synthesis. 2023; 21(3), 472-477.
  2. Boutron I, Page MJ, Higgins JPT, Altman DG, Lundh A, Hróbjartsson A. Chapter 7: Considering bias and conflicts of interest among the included studies. In: Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (Eds). Cochrane Handbook for Systematic Reviews of Interventions version 6.3 (updated February 2022). Cochrane, 2022. Available from www.training.cochrane.org/handbook.
  3. Ledbetter, Leila S, and Steph Hendren. Quality assessment and risk of bias tool repository.” OSF, 15 Jan. 2025. Web. doi:10.17605/OSF.IO/WS824.
  4. Grant MJ & Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Information & Libraries Journal. 2009; 26(2), 91-108.

 

Article Spotlight

Not sure if your synthesis type requires risk of bias assessment?

The following table provides a typology of review types that specifically indicates whether or not critical appraisal is generally a component of 14 different reviews types Table 1: Main review types characterized by methods used [3].

Resource Spotlight

Not sure which tool to use? 

Check out the Quality Assessment and Risk of Bias Tool Repository for finding and selecting a risk of bias or quality assessment tool for evidence synthesis projects [4]. This project was created and is maintained by Duke University's Medical Center Library & Archives.