What Is Marketing Attribution?
Attribution is the process of crediting marketing touchpoints for sales. Get it wrong and you'll invest in the wrong channels.
Key Takeaways
- Attribution assigns credit to marketing touchpoints that contributed to a conversion.
- Last-click attribution is the default — but it over-credits conversion channels and under-credits awareness.
- No attribution model is perfect; the goal is to reduce bias, not eliminate uncertainty.
The attribution problem
A customer might see a Facebook ad on Monday, click a Google Shopping ad on Wednesday, open an email on Friday, and then buy through a direct visit on Sunday. Which channel gets credit for the sale? Attribution is the process of answering that question — and the answer significantly affects how you allocate your marketing budget.
Common attribution models
Last-click: 100% credit to the final touchpoint before conversion. Simple but biased toward lower-funnel channels. First-click: 100% credit to the channel that first introduced the customer. Overvalues discovery channels. Linear: equal credit across all touchpoints. Time-decay: more credit to touchpoints closer to conversion. Data-driven: algorithmic model based on your actual conversion path data (requires sufficient volume).
Why last-click is dangerous
Last-click attribution makes retargeting and branded search look very effective (they convert customers who were already going to buy), and makes social media awareness campaigns look ineffective (they drive customers who ultimately convert through other channels). Businesses optimising purely on last-click ROAS systematically underinvest in awareness and discovery channels.
Practical approaches
Use platform data (last-click ROAS) as a starting point, but complement with incrementality tests for major channels. Run a media mix model annually if your ad spend is above £100,000. Use UTM parameters consistently to track channel contributions accurately. Most importantly, look at revenue trends when you scale or cut specific channels — the market response is the ultimate attribution signal.