CRA Systematic Review & Meta-Analysis 2 ā Questions and Answers
Question 1: Which statistical measure quantifies the degree of inconsistency among studies in a meta-analysis?
- Cohen's d
- IĀ² statistic (Correct answer)
- Pearson's r
- Bayes factor
Correct answer: IĀ² statistic
The IĀ² statistic estimates the proportion of total variation across studies attributable to heterogeneity rather than chance.
Question 2: A funnel plot in meta-analysis is primarily used to detect:
- Heterogeneity between studies
- Publication bias (Correct answer)
- Confounding variables
- Selection bias within studies
Correct answer: Publication bias
Funnel plots display study effect sizes against their standard errors, and asymmetry suggests potential publication bias.
Question 3: In a systematic review, what does a PRISMA flow diagram document?
- Statistical heterogeneity across included studies
- The number of records identified, screened, and included/excluded (Correct answer)
- Risk of bias ratings for each included study
- Forest plot data from the meta-analysis
Correct answer: The number of records identified, screened, and included/excluded
PRISMA flow diagrams transparently track the study selection process from initial database searches through final inclusion.
Question 4: Which model assumes that the true effect size varies across studies and should be used when substantial heterogeneity exists?
- Fixed-effects model
- Random-effects model (Correct answer)
- Bayesian hierarchical model
- Mixed-effects ANOVA
Correct answer: Random-effects model
The random-effects model accounts for between-study variance (ĻĀ²), making it appropriate when studies estimate different underlying true effects.
Question 5: The Cochrane Risk of Bias tool (RoB 2) assesses bias across which domain specific to randomization?
- Attrition bias
- Detection bias
- Bias arising from the randomization process (Correct answer)
- Reporting bias
Correct answer: Bias arising from the randomization process
RoB 2's first domain evaluates whether the randomization sequence was adequately generated and concealed.
Question 6: When two independent reviewers disagree on study inclusion in a systematic review, the recommended resolution method is:
- Automatically excluding the study
- Deferring to the more senior reviewer
- Discussion until consensus or third-reviewer arbitration (Correct answer)
- Coin-flip randomization
Correct answer: Discussion until consensus or third-reviewer arbitration
Consensus discussion, with arbitration by a third reviewer if needed, maintains objectivity and reduces individual reviewer bias.
Question 7: Which approach involves updating a systematic review as new evidence emerges, without a fixed end date?
- Rapid review
- Scoping review
- Living systematic review (Correct answer)
- Narrative synthesis
Correct answer: Living systematic review
Living systematic reviews are continuously updated, making them especially valuable for fast-moving research areas or clinical guidelines.
CRA Systematic Review & Meta-Analysis 2
Which statistical measure quantifies the degree of inconsistency among studies in a meta-analysis?