Reading payback windows without fooling yourself
A payback window is the number of days until cumulative contribution from a cohort covers what you spent to acquire those people. It sounds simple until refunds, delayed second purchases, and incomplete source tags enter the picture.
Start from repurchase rhythm
If your category typically sees a second order around day forty, a seven-day payback target will punish channels that still produce healthy lifetime value. Align the window with observed repurchase timing before you grade media partners.
Separate contribution from revenue
Gross order value inflates the story when discounts and payment fees are large. Contribution after variable costs keeps customer lifetime value conversations honest with finance.
Document thin cohorts
Early months after launch often have too few buyers for stable estimates. Mark those cohorts as directional so leadership does not treat a noisy spike as a new normal.