Appraisal of a study


  • Are the aims stated?
  • Literature reviewed?
  • Relevant to GP, to my patients?
  • Does study simply replicate others or offer something new?


  • Is study design appropriate?
    • qualitative/quantitative
    • observational/experimental
    • retrospective/prospective
    • longitudinal/cross-sectional


  • Are they appropriate to concepts?
  • Have they been validated in practice?


  • Recruitment
    • Are study and control groups equally matched?
    • Age/sex/class
    • Were they recruited in the same way?
    • Sensible inclusions, clear criteria?
    • Do exclusions influence applicability?
    • Subjects studied in “real life” circumstances?
  • Design
    • Are the intervention and comparison clear?
    • Are outcome criteria defined?
    • What was actually measured or done? (Beware surrogate markers)
    • Is sample size sufficient? (To indicate clinical and statistical significance) was “power” calculated?
      b-error = no effect seen when one exists -due to small sample size
      a-error = significant effect due to sampling error
    • Is randomsation/allocation described? Is it concealed?
    • Was assessment blind?
    • Remember biases
      • selection/inclusion
      • performance
      • exclusion
      • detection
    • Follow up – were completeness and duration OK?


  • Consider drop outs/exclusions (analysis by intention to treat?)
  • Are tables and graphs honest?
  • Are statistics appropriate? – CI’s, p-values.
  • Is clinical significance achieved?
  • Were all subjects accounted for at the conclusion of the study?


  • Aware of methodological/design limitations?
  • Conclusions justified?
  • Compare with previous work?
  • Are speculations appropriate and realistic?

Application of findings

  • Are the patients comparable to your own?
  • Is the setting comparable?
  • Are the results clinically significant?
  • Is the intervention feasible in your own practice setting?
  • Is it affordable, available and sensible?
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