Regression Discontinuity Lab: Gaokao
Learn why RD only works at the true discontinuity. Elite college admission occurs at 580; try a placebo cutoff elsewhere and see how the estimated “effect” disappears or flips.
Parameters
Try 580 for valid RD, other values for placebo cutoff
Income benefit of elite college (10k RMB)
Students manipulate scores above 580
Try These
RD Analysis at Cutoff 580 (True Elite Cutoff: 580)
Results
Analysis Details
Performance
Key RD Lessons
Why Cutoff Matters
RD only works when you analyze at the TRUE discontinuity. Analyzing at placebo cutoffs produces weak/no effects because there's no actual policy change there.
Real-World Application
In practice, researchers must know institutional details to identify true cutoffs. Fishing for effects at arbitrary thresholds invalidates the design.
Experiment: Try setting the analysis cutoff to 560 or 600. Notice how RD finds little effect even though elite colleges have a real impact!
Stata Implementation
Master All Causal Inference Methods
Now you understand how RD depends on knowing the true discontinuity. Compare this with other quasi-experimental methods that identify causal effects.