Critical appraisal has been described as "the process of carefully and systematically examining research to judge its trustworthiness, and its value and relevance in a particular context" (Burls, 2009).

• Has the research been conducted in a way that minimises bias? (Is it trustworthy?)

• What is the impact and importance of the findings? (What is the research's value?)

• Are the results applicable to your patient/population/problem? (Is it relevant to your research question?)

Burls, A. (2009). What is critical appraisal? https://www.sheffieldchildrens.nhs.uk/download/292/illingworth-library/8435/what-is-critical-appraisal-training-guide.pdf

Tools

Tools for quick appraisal

• The RAMMbo mnemonic:

- Recruitment – were the participants in the study representative of the target population? What was the sample size?

- Allocation – was the trial randomised?   

- Maintenance – Was the status of the control group and study group maintained throughout the trial?  Were they treated the same way, other than in the intervention?  

- Measurement (Blinding, Objective measures) – were the outcomes measured objectively and the participants blinded to the intervention?  Was bias eliminated as much as possible?
 

• Understanding Health Research - a checklist of questions about an article.

Tools for a more thorough appraisal

• Critical appraisal tools - interactive, with links to resources on how to identify the study type and build your critical appraisal skills
• AMSTAR checklist - Assessing the Methodological Quality of Systematic Reviews
• Resources [for critical appraisal] - from the Centre for Evidence-based Veterinary Medicine, University of Nottingham - appraisal tools for different study types
• Checklists for appraising study qualities - from the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN)
• Critical Appraisal Skills Programme (CASP) - eight critical appraisal tools for different levels of research
• Eco-Evidence - tools for the evaluation of evidence from environmental science literature. You will need to register to use the tools.
• Critical Appraisal - some checklists and an app from this Center for Evidence-Based Management in The Netherlands.

• QuOCCA - The Quality Output Checklist and Content Assessment is a critical appraisal tool intended to assess the trustworthiness of published, peer reviewed original research papers.

Resources

• Buccheri and Sharifi (2017) outline the uses, strengths and weaknesses of various appraisal tools for nursing research in their paper, Critical appraisal tools and reporting guidelines for evidence‐based practice. Worldviews on Evidence‐Based Nursing, 14(6), 463-472. https://doi.org/10.1111/wvn.12258
   
• The How to read a paper series from the British Medical Journal links to articles that explain how to read and interpret different kinds of research.

• Trisha Greenhalgh's book How to read a paper, is an extension of this.
   
• Salisbury, J., Glasziou, P., & Del Mar, C. (2007). Evidence-based practice workbook: Bridging the gap between health care research and practice (2nd ed.). Oxford: Blackwell/BMJ Books.
   

Study Designs

Sometimes it's difficult to identify the study design of a particular paper. The Study Designs article from the Centre for Evidence Based Medicine in the UK provides a guide to the different study types and a comparison of the advantages and disadvantages of each.