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Sport, Rehabilitation and Exercise Sciences

Critical Appraisal

Checking the validity and value of papers
As well as checking that your results are relevant to your research topic, you will also need to ensure that they are valid and valuable e.g. unbiased, objective etc.This process is known as critical appraisal.

Tools for Critical Appraisal

  • Research is the process by which we generate knowledge.
  • Different research questions require different study designs.
  • Bias is the systematic deviation of the findings of studies from the truth. All studies can be subject to bias, but some study designs are more prone to bias than others.
  • It is important that researchers take steps to reduce bias so that studies are valid and their results trustworthy. When testing whether a treatment is effective, a randomised controlled trial is the best design to minimise bias.
  • Odds ratios, risk ratios and number needed to treat are ways of expressing results in quantitative studies.
  • Critical appraisal is the process of carefully and systematically examining a research report to judge its trustworthiness, make sense of the results and assess the relevance of the findings in a particular context.
  • Systematic reviews systematically collect, appraise, report and, where appropriate, combine all the trustworthy scientific evidence from individual studies. They are therefore the best study design to choose to inform decisions.
  • The Critical Appraisal Skills Programme aims to help people develop the necessary skills to make sense of scientific evidence, and has produced appraisal checklists covering the validity, results and relevance of different study designs, including systematic reviews. You can download these free of charge at


A number of checklists have been developed to help with the process of critically appraising articles from various types of studies:

This tool will guide you through a series of questions to help you to review and interpret a published health research paper.

On this page you will find links to articles in the BMJ that explain how to read and interpret different kinds of research papers.This series of articles are by Trisha Greenhalgh, one of the key experts on critical appraisal.