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Critical Appraisal : Where to start

Key questions to ask when doing critical appraisal

Key questions to start your critical appraisal with (Greenhalgh 2019)

1. What is the research question and why is the study needed?  

2. What was the research design? (Your choice of checklists will depend on the study design)

3. Was the research design appropriate to the question?

Greenhalgh, T., 2019. How to read a paper: the basics of evidence-based medicine and healthcare. Hoboken: Wiley-Blackwell.  

Before you can critically appraise the methodology, you need good understanding of research methods for the discipline in question and the correct choice of study design for the research question at hand. If you are not familiar enough with these, read a book on research methods in the discipline in question.

1. Was the study original?

2. Whom is the study about?

3. Was the study design suitable for the research question?

4. Was bias avoided or minimised? 

5. Was assessment "blind"?

6. Were preliminary statistical questions addressed? 

Greenhalgh, T., 2019. How to read a paper: the basics of evidence-based medicine and healthcare. Hoboken: Wiley-Blackwell.  

 

It is vital to assess bias when critically appraising a research paper. Bias can happen both on the respondents' side and on the researchers' side and it can occur at any stage in the research process side in study design, in sample selection, in data collection and interpretation etc. For more information on bias see the resources on the next page of the guide.

To enable you to critically appraise quantitative research, understanding of basic statistics is required. You need to be able to appraise the authors' interpretation of the study results as sometimes the interpretation can be incorrect, biased or misleading. 

See resources on Interpreting statistics on the Critical appraisal tools and checklists tab of this guide.  

 

Critical appraisal tutorials

Critical analysis quiz  from the London School of Hygiene & Tropical Medicine 

Critical appraisal for medical and health sciences from the University of Manchester

Finding and appraising the evidence (online tutorial by Health Knowledge)

GRADE Online Learning Modules

Understanding Health Research A tool for making sense of health studies from MRC?CSO Social and Public Health Sciences Unit, University of Glasgow