Crowe Critical Appraisal Tool (v1.4)

Summary of main points

  • The Crowe Critical Appraisal Tool (CCAT) consists of
  • Always use the CCAT Form and the CCAT User Guide together.
  • Research designs should be appraised on their own merits, not to a ‘gold standard’.
  • All categories must be scored: it does not matter which research design was used
    • The lowest score for a category is 0, the highest score is 5
    • Category scores are whole numbers only (that is 0, 1, 2, 3, 4, or 5)
    • The score for each category must be reported
    • The total score (out of 40 or as a percent) is reported in addition to each category score.
  • Item descriptors may be marked present (✔), absent (✘), or not applicable (◼).
    • Tick marks are not a check list to be totalled.
    • Tick marks are simply a guide to scoring a category.
  • If in doubt use your best judgement, there is no right or wrong answer.


Crowe, M., Sheppard, L., & Campbell, A. (2011). Comparison of the effects of using the Crowe Critical Appraisal Tool versus informal appraisal in assessing health research: a randomised trial. International Journal of Evidence-Based Healthcare, 9(4), 444–449.
Crowe, M., Sheppard, L., & Campbell, A. (2012). Reliability analysis for a proposed critical appraisal tool demonstrated value for diverse research designs. Journal of Clinical Epidemiology, 65(4), 375–383.
Crowe, M., & Sheppard, L. (2011). A general critical appraisal tool: an evaluation of construct validity. International Journal of Nursing Studies, 48(12), 1505–1516.
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), 79–89.