Regression-Discontinuity Design - Institute for Policy Research

Issue 2: To pool or not pool across multiple
cutoff points?
• The benefit of the design is that in theory, we can
estimate the average treatment effect across an
interval of cutoffs (τ mc ).
– If we include treatment x cutoff group interactions, we
could also look at heterogeneous effects by cutoff.
• The concern, however, is that pooling across multiple
cutoffs obscures sources of heterogeneity because
cutoffs often vary by sites, time, cohorts, grades, etc.