Evaluate Post-Purchase Recommendation Emails

A retailer wants to send recommendation emails after a customer completes a purchase. You must determine if this feature is worth building and design a test for it. Before picking a model, discuss the product recommendations, timing, business value, and potential downsides.

Constraints & Assumptions

The discussion highlighted product and business logic. It brought up retention cost relative to acquisition cost and negative outcomes like unsubscribes and spam reports. Consider lower retention cost as a hypothesis to test for this business, not an established truth.

Clarifying Questions

What outcome would make the email worthwhile? Which customers are eligible and have opted into this channel? Are the recommendations for complementary items, replenishment, or something else? What limits exist on contact frequency and timing?

What a Strong Answer Covers

Contrast sending the email against not sending it, calculate incremental value net of costs and customer harm, select a sensible baseline, and design a randomized experiment with guardrails for engagement and channel health.

Follow-up Questions

How would you separate a purchase caused by the email from one that would have happened regardless? What if open rates increase but unsubscribes increase too? How would a recent return or a bad delivery experience affect eligibility?

Overview: Assess post-purchase recommendation emails by considering incremental profit, appropriate timing, customer eligibility, randomized control groups, and guardrails for unsubscribes or complaints.