majiayu000 Designing Experiments
Helps select the appropriate causal inference method.
Decision Framework
Control Group?
- Yes: Go to Step 2.
- No: Consider Interrupted Time Series (ITS).
Unit Structure?
- Single Treated Unit:
- With multiple controls: Synthetic Control (SC).
- No controls: ITS.
- Multiple Treated Units:
- With control group: Difference-in-Differences (DiD).
- Single Treated Unit:
Time Structure?
- Panel Data (Multiple units over time): Required for DiD and SC.
- Time Series (Single unit over time): Required for ITS.
Method Quick Reference
- Difference-in-Differences (DiD): Compares trend changes between treated and control groups. Assumes Parallel Trends.
- Interrupted Time Series (ITS): Analyzes trend/level change for a single unit after intervention. Assumes Trend Continuity.
- Synthetic Control (SC): Constructs a synthetic counterfactual from weighted control units. Assumes Convex Hull (treated unit within range of controls).