| name | subgroup-analysis |
| description | Conduct subgroup analyses to examine effect moderation. Use when: (1) Testing pre-specified moderators, (2) Exploring heterogeneity, (3) Identifying differential effects, (4) Meta-analysis synthesis. |
| allowed-tools | Read, Write, Bash |
| version | 1.0.0 |
Subgroup Analysis Skill
Purpose
Examine whether effects differ across subgroups of participants or studies.
Planning Subgroup Analyses
Pre-Specify:
- Which subgroups (age, sex, severity)
- Rationale for each
- Statistical approach
Limit Number:
- Too many = Type I error inflation
- Focus on theoretically important
- Correct for multiple comparisons
Subgroup Analysis Methods
1. Interaction Tests
- Test group × subgroup interaction
- More powerful than separate analyses
2. Stratified Analysis
- Separate analysis per subgroup
- Compare effect sizes
3. Meta-Regression
- Continuous moderators
- Multiple moderators simultaneously
Interpretation Cautions
Observational Nature:
- Subgroups not randomized
- Confounding possible
- Generate hypotheses, don't confirm
Multiple Testing:
- Adjust alpha (Bonferroni)
- Or report as exploratory
Example:
"Pre-specified subgroup analysis showed larger effects in younger participants (<50 years, d=0.68) versus older (≥50 years, d=0.34), interaction p=.02."
Version: 1.0.0
