Qm
Statistics

The loyalty program that looked good until you checked

difference-in-differencescausal-inferenceretail

A retailer launches a loyalty program at Store A and uses Store B as a control. Monthly sales before and after, in thousands of dollars:

  • Store A (treated): 100 before, 110 after.
  • Store B (control): 120 before, 138 after.

Compute the difference-in-differences estimate, and interpret the sign.

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