Did Affiliate Performance Improve, or Did the Placement Mix Change?

A media buyer sees approved earnings per click rise the week a new creative goes live. Before giving the creative more budget, check which placements supplied the clicks. A change in traffic allocation alone can produce the entire apparent lift.

Rebuild the total with the earlier click shares

Suppose a newsletter earns $0.80 per click and a comparison page earns $0.20. In week one, each supplies half the clicks, so combined EPC is $0.50. In week two, the newsletter supplies three quarters. Even if neither placement improves, combined EPC becomes $0.65. That extra $0.15 is real in the account, but it is poor evidence that the new creative persuaded more readers.

For a fixed-share comparison, multiply each week-two placement EPC by its week-one share of clicks, then add the results. Here the answer is still $0.50. Use the same click definition, currency and approval window for both weeks. Set new placements aside in a separate row: a placement with no earlier clicks has no baseline rate to compare.

Match the decision to the evidence

A shift toward the newsletter may be profitable if the additional clicks are available at a workable cost. That is a placement decision. To assess the creative, compare variants within the same placement over the same period, ideally with randomized allocation. For affiliate media buyers, keeping both views in the report preserves the actual payout while making clear which change still needs a test.