13 attribution mistakes most brands fall into

most attribution problems aren't methodology debates, they're boring setup issues that quietly cost money. a running list of the ones that come up most often.

1. last-click is still the default in most platforms and almost universally wrong. it overcredits whatever sits closest to checkout.
2. attribution windows aren't comparable across platforms. meta runs 7-day click / 1-day view, ga4 is configurable, shopify is last-click on conversion date. comparing without normalizing creates fake discrepancies.
3. utm hygiene gaps. inconsistent or missing utms push 20-40% of paid traffic into ""direct"" in ga4. step zero before buying any tool.
4. running capi without proper deduplication. pixel + capi firing the same purchase without matching event_id is the biggest reason meta over-reports.
5. trusting view-through conversions at face value. 1-day-view on retargeting can inflate roas 20-50%.
6. defaulting to roas instead of mer. roas is per-channel. mer (total revenue / total ad spend) is what the cfo actually cares about and surfaces cross-channel cannibalization.
7. using mta for strategic budget decisions. mta is a tactical signal for creative and audience. it can't see what didn't happen and shouldn't drive cross-channel allocation.
8. skipping incrementality testing. holdouts and geo-lifts are the only reliable read on whether a channel is actually incremental.
9. buying an attribution tool too early. under ~$1m revenue, mta tools won't move the needle. fix utms, capi, and ga4 setup first.
10. ignoring modeled conversions. an increasing share of platform-reported conversions are modeled, not measured, and the share grows every quarter.
11. treating branded search as acquisition. branded search captures demand that already exists. crediting it to acquisition overstates roas and starves the channels that actually create demand.
12. post-purchase survey. pps tools are the cheapest sanity check for word-of-mouth, podcast, and community conversions that no pixel sees.
13. forgetting ai-driven traffic. chatgpt, claude, and perplexity strip referrer headers, so generative search lands in ""direct"" and gets re-targeted as cold. tag it server-side or lose it.

anything missing? what else keeps showing up?