Steps to appraising an RCT:
Source for most info on this page; Critical appraisal of randomised controlled trials by Nik Bobrovitz, October 2016
1. Find an RCT that addresses your clinical question
Limit your search to "Randomized Control Trials" in the following databases:
2. Assess the risk of bias and decide if the results are trustworthy.
Validity
If a study is internally valid we then assess the study’s external validity a.k.a. generalizability
External validity: the extent to which the results apply outside the study setting
3. Determine if the effect is significant and generalizable
Significance:
External validity: were the patients and setting in the study similar to ours?
Consider:
What is a randomized controlled trial?
In RCTs the experimental and comparison groups are equal in size.
Table 8.4.a: A common classification scheme for bias
Type of bias |
Description |
Relevant domains in the Collaboration’s ‘Risk of bias’ tool |
Selection bias. |
Systematic differences between baseline characteristics of the groups that are compared. |
|
Performance bias. |
Systematic differences between groups in the care that is provided, or in exposure to factors other than the interventions of interest. |
|
Detection bias. |
Systematic differences between groups in how outcomes are determined. |
|
Attrition bias. |
Systematic differences between groups in withdrawals from a study. |
|
Reporting bias. |
Systematic differences between reported and unreported findings. |
|
Source: Higgins, J. P. and Altman, D. G. (2008). Assessing Risk of Bias in Included Studies. In Cochrane Handbook for Systematic Reviews of Interventions (eds J. P. Higgins and S. Green). doi:10.1002/9780470712184.ch8