Health Evidence Bulletins - Wales: Questions to
assist with the critical appraisal of a randomised controlled trial (Type II evidence)
Adapted from the CASP questions (taken from Guyatt et al. Users' guides to the medical literature. II How to use an article about therapy or prevention. Journal of the American Medical Association. 1993; 270: 2598-2601 and 271: 59-63) and Barker, JM. Project for the enhancement of the Welsh Protocols for Investment in Health Gain. Project Methodology. Cardiff: Duthie Library. UWCM, 1996.
A/ What is this trial about and can I trust it?
|1. Is the trial relevant to the needs of the Project?|
|2. Did the trial address a
clearly focused issue?
in terms of:
|3. Was the assignment of patients to treatments randomised?|
|4. Were all the patients who
entered the trial properly accounted for at its conclusion?
|5. Were patients, health
workers and study personnel 'blind' to treatment?
|6. Were the groups similar at
the start of the trial?
In terms of all the factors that might be relevant to the outcome:
age, sex, social class, life style etc.
|7. Aside from the experimental intervention, were the groups treated equally?|
Is it worth continuing?
B/ What did they find?
|8. How large was the treatment
|9. How precise was the
estimate of the treatment effect?
C/ Are the results relevant locally/to me?
|10. Can the
results be applied to the local population?
Do you think the patients covered by the trial are similar enough to your population? Consider culture, geography etc.
|11. Were all
important outcomes considered?
If not, does this effect the conclusion(s)?
|12. Is any information provided which could help you decide whether the benefits are worth the harms/costs (financial and otherwise)?|
|13. Accept for further use as Type II evidence?||Refer to Team Leader|
Draft Statement (if appropriate):
(Remember to include the relevant target group (age range, sex etc.); the measured outcomes/benefits with quantitative information if available; and the health gain notation)