11 questions to help you make sense of a Case Control Study
How to use this appraisal tool: Three broad issues need to be considered when appraising a
case control study:
Are the results of the study valid? (Section A)
What are the results? (Section B)
Will the results help locally? (Section C)
The 11 questions on the following pages are designed to help you think about these issues
systematically. The first three questions are screening questions and can be answered
quickly. If the answer to both is “yes”, it is worth proceeding with the remaining questions.
There is some degree of overlap between the questions, you are asked to record a “yes”,
“no” or “can’t tell” to most of the questions. A number of italicised prompts are given after
each question. These are designed to remind you why the question is important. Record your
reasons for your answers in the spaces provided.
About: These checklists were designed to be used as educational pedagogic tools, as part of a
workshop setting, therefore we do not suggest a scoring system. The core CASP checklists
(randomised controlled trial & systematic review) were based on JAMA 'Users’ guides to the
medical literature 1994 (adapted from Guyatt GH, Sackett DL, and Cook DJ), and piloted with
health care practitioners.
For each new checklist, a group of experts were assembled to develop and pilot the checklist
and the workshop format with which it would be used. Over the years overall adjustments
have been made to the format, but a recent survey of checklist users reiterated that the basic
format continues to be useful and appropriate.
Referencing: we recommend using the Harvard style citation, i.e.: Critical Appraisal Skills
Programme (2018). CASP (insert name of checklist i.e. Case Control Study) Checklist. [online]
Available at: URL. Accessed: Date Accessed.
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