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Systematic Reviews for Health Sciences and Medicine

An introduction to systematic reviews, with examples from health sciences and medicine

Critical Appraisal

Critical appraisal is the process of judging the validity and quality of a research paper.

Major points to consider when appraising systematic reviews include:

  • Is the study valid?

  • What are the results, and are they significant?

  • Are the results applicable?

 

Critical Appraisal Tools

Critical Appraisal Skills Programme (CASP)
Ten questions to help you make sense of a systematic review

AMSTAR 2
A critical appraisal tool for systematic reviews that include randomised or non-randomised studies of healthcare interventions, or both

STROBE
Designed for epidemiological studies

EQUATOR
Network listing over 300 sets of reporting guidlelines

Crowe, M., & Sheppard, L. (2011). A review of critical appraisal tools show they lack rigor: alternative tool structure is proposed. Journal of clinical epidemiology, 64(1), 78-89.

 

Checklists

PRISMA checklist
Not a quality instrument but helpful for identifying elements to look for in a systematic review. 

SPIRIT checklist
Not a quality instrument but helpful for identifying elements to look for in a systematic review. 

 

Further Reading


Greenhalgh, T. (1997). The Medline database. BMJ, 315(7101), 180-183. Full Text

Greenhalgh, T. (1997). Getting your bearings (deciding what the paper is about). BMJ, 315(7102), 243-247. Full Text

Greenhalgh, T. (1997). Assessing the methodological quality of published papers. BMJ, 315(7103), 305-308. Full Text

Greenhalgh, T. (1997). Statistics for the non-statistician: different types of data need different statistical tests. BMJ, 315(7104), 364-366. Full Text

Greenhalgh, T. (1997). Statistics for the non-statistician. II:“Significant” relations and their pitfalls. BMJ, 315(7105), 422-425. Full Text

Greenhalgh, T. (1997). Papers that report drug trials. BMJ, 315(7106), 480-483. Full Text

Greenhalgh, T. (1997). Papers that report diagnostic or screening tests. BMJ, 315(7107), 540-543. Full Text

Greenhalgh, T. (1997). Papers that tell you what things cost (economic analyses). BMJ, 315(7108), 596-599. Full Text

Greenhalgh, T. (1997). Papers that summarise other papers (systematic reviews and meta-analyses). BMJ, 315(7109), 672-675 Full Text

Greenhalgh, T., & Taylor, R. (1997). Papers that go beyond numbers (qualitative research). BMJ, 315(7110), 740-743. Full Text

 

Data Extraction

Data extraction is the process of transcribing information from the primary studies under review to a standard form or template that has been designed to capture all of the detail relevant to the meta-analysis.

Double data extraction is preferred for accuracy - this is when two researchers extract the data independently and discuss any discrepancies or consult a moderator to arrive at consensus.
 

Further Reading

Buscemi, N., Hartling, L., Vandermeer, B., Tjosvold, L., & Klassen, T. P. (2006). Single data extraction generated more errors than double data extraction in systematic reviews. Journal of clinical epidemiology, 59(7), 697-703. Full Text