Randomised splitRecommended
New applications split 50/50 at decision time. Both groups live through the same market and the same policy drift, so nothing else has to be held constant.
11 weeks minimum2,400 applicationsdetects 1.5 pp
Staged rollout, then before and afterConditions apply
Live for everyone from a date, measured against a segment left alone. Needs a clean record of everything else that changed in the window.
difference in differences3 confounding changes found
Retrospective, from the existing cutoffNo change required
Applications either side of the current threshold are alike apart from which side they fell. That discontinuity already sits in your history.
regression discontinuity1,870 cases in bandwidthanswer in days
Illustrative example. Method availability depends on volumes and what else is changing.