The post-purchase survey data everyone collects and nobody uses

A post-purchase "how did you hear about us" survey is cheap to implement and, at most companies that run one, the responses sit in a spreadsheet or a dashboard tab that nobody revisits after the initial setup. That's a missed opportunity, because self-reported attribution, imperfect as it is, is one of the few signals available that isn't entirely dependent on the platform grading its own homework.

The value isn't in treating survey responses as precise attribution, they're not, memory is unreliable and multi-touch journeys get compressed into whatever channel the customer remembers most vividly. The value is directional: comparing self-reported channel mix against platform-reported attribution over time reveals where the platforms are most likely overclaiming credit.

The practical use: if platform-attributed conversions from a channel are growing while that same channel's share of survey responses stays flat or declines, that's a signal worth investigating before scaling that channel further, a cheap early warning that a more rigorous incrementality test would take weeks and real budget to confirm.

This isn't a replacement for proper incrementality testing. It's a nearly free, always-on signal most businesses already collect and never look at, sitting quietly in a spreadsheet next to data that could actually change a budget allocation decision if anyone opened the tab.