SYS/DEF
Attribution
The rule that decides which touch “owns” a conversion — last click, data-driven, or a blend nobody read.
Definition
Attribution is the convention that splits credit for a conversion across journey touches. Last click gives everything to the last paid click; first click to the first; linear shares; data-driven claims to learn the weights. None of these is the truth of the journey: they are accounting keys.
Changing model moves euros from one channel to another without a single visitor changing behaviour. That is why a “higher” ROAS after an attribution switch is not an acquisition gain.
When it matters
It matters when you read a SEA campaign or a SEO/SEA mix, and when you write the tracking plan: if the dataLayer does not send the same conversion id to Google Ads and to analytics, the two tools will tell two stories.
It also matters when you compare a CRO test to a campaign: the test measures a delta on a page; attribution measures credit. Adding them without saying so produces confused committees.
Pitfalls
The expensive trap is steering bids on one model and reporting to the board on another. The second is treating the platform’s data-driven model as a scientific measurement: it is trained on conversions the platform sees, not yours. The third: ignoring the window (7 days, 30 days, view-through) when comparing two periods.
Related terms
Related tool
Spend, conversions and revenue turned into CPA and ROAS — the arithmetic does not lie; attribution upstream might: Open CPA and ROAS.