Campbell-Style Designs
Randomized Pre–Post Designs
A baseline and follow-up outcome become especially informative when treatment is assigned at random.
Page 1 of 7 · Big Picture
The big picture: Randomized Pre–Post Designs
What does randomization add to a before-and-after comparison?
Why a policy analyst should care
Randomization makes treatment groups comparable in expectation, while baseline outcomes can reveal chance imbalance and improve precision without defining the effect by themselves.
Follow the idea from the opening question to a practical decision. These are the conceptual moves this module will develop:
1 Question What does randomization add to pre–post change?
2 Explore Random assignment creates the comparison
3 Formalize Compare changes by assignment
4 Transfer Defend a randomized policy evaluation
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