Hot take ·
Last-click attribution is lying to you
Last-click attribution gives 100% of the credit for a sale to the final ad someone tapped. That single rule systematically overpays your bottom-funnel search and retargeting, and starves the awareness channels that actually created the demand — so you cut the ads that were working.
Here is the uncomfortable part: the report your ad platform shows you by default is designed to make that same platform look good. Last-click attribution is the industry's most popular measurement model, and it is quietly one of the most expensive mistakes a growing business can make.
What is last-click attribution?
Last-click attribution is a model that assigns 100% of the credit for a conversion to the last ad or channel a customer interacted with before buying. If someone discovers you on radio, sees three Instagram posts, then searches your brand name and clicks a Google ad, last-click hands the entire sale to Google. The radio and the Instagram posts — the reason they searched at all — get nothing.
Why is that a problem?
Because you allocate budget based on what your report rewards. When the report only rewards the final touch, you pour money into brand search and retargeting — channels that mostly harvest demand that already existed — and you cut the upper-funnel channels that created it. The numbers look great right up until growth stalls, because you have optimised your way into only ever talking to people who were already going to buy.
What should you use instead?
You do not need a data-science team to do better than last-click. In order of effort:
- Incrementality tests. Turn a channel off in one region, leave it on in a comparable one, and measure the difference in sales. This tells you what a channel actually caused, not what it happened to be near.
- Marketing mix modelling (MMM). A statistical view of how every channel — including radio, TV, and billboards you can't put a pixel on — contributes to revenue. It works without cookies, which matters more every year.
- At minimum, a position-based model. Even splitting credit across first touch, middle, and last touch is closer to the truth than giving everything to the end.
The one-line version
If you only measure the last click, you will keep defunding the top of your funnel until there is nothing left to harvest. Measure what each channel causes, and your break-even maths changes — often dramatically.
Track it live in ROAS Intelligence
Joolr's ROAS Intelligence platform connects your ad channels and payment rails — so you can see which "winners" are really just harvesting demand, in real time.
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