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What is critical appraisal?

typing on a computer

Critical appraisal is a crucial part of evidence-based medicine, yet reading and critiquing a journal article can seem like a daunting and complex task. Breaking the process down into steps should enable you to build up the necessary skills, such as:

- Skimming the article in the first instance to look for the author's main points and conclusions

- Being familiar with the way that many journal articles are structured (abstract, method, results, discussion etc)

- Reflecting on and being critical of what you are reading

A checklist or toolkit such as those on this page will guide you through this process in a structured way. This page will also direct you to articles, web pages, online guides and books to guide you toward effectively appraising scientific articles.

If you have any suggestions for helpful books, links, or resources about critical appraisal please email library@kcl.ac.uk

Statistics

Trustworthiness assessment

Abstract
Background
There is increasing concern that a significant proportion of randomized controlled trials (RCTs) included in Cochrane reviews may not be trustworthy. Applying the Cochrane Pregnancy and Childbirth Trustworthiness Screening Tool (CPC-TST) has already had a clinically important effect on several reviews published by the Cochrane Pregnancy and Childbirth Group.

Objectives
We wanted to assess the impact of removing untrustworthy RCTs from already-published Cochrane reviews on a defined clinical area (antenatal and postnatal nutritional interventions).

Methods
We applied the tool to 18 Cochrane reviews (374 RCTs). The tool had four domains: (i) is the research governance trustworthy; (ii) are the baseline characteristics trustworthy; (iii) is the study feasible; (iv) are the results plausible? When additional information was needed, authors were contacted using a standard template. At least two attempts were made to contact the authors. At the end of the evaluation process each study was classified as: (i) included (YES to all questions); (ii) excluded (retracted study); or (iii) awaiting classification (any NO to the questions).

Results
Ninety-three out of 374 included studies (25%) were reclassified as “excluded” or “awaiting classification.” The number of included RCTs was reduced in 14 out of 18 reviews. Six reviews (33%) were judged to require updating because of important differences in the Summary of Findings tables (direction and size of effects and/or GRADE ratings), conclusions, implication for practice, and/or implication for research.

Conclusions
Formal assessment of trustworthiness, and inclusion only of studies that satisfy prespecified criteria for trustworthiness, affect conclusions in a relatively large number of Cochrane reviews, with potentially important clinical implications for practice and research.

Weeks J, Cuthbert A, Alfirevic Z. Trustworthiness assessment as an inclusion criterion for systematic reviews—What is the impact on results? Cochrane Ev Synth. 2023;e12037. doi:10.1002/cesm.12037

Toolkits and checklists for critical appraisal

Helpful links

Books and ebooks

New books are published regularly on the topic of reading a paper, study skills, critical appraisal etc - click the books below or use Library Search to explore books in our collection:

New to using Library Search?

You can find online tutorials on using Library Search to find books and journals around your subject. Find them in the Getting Started With Your Studies section of KLaSS: