Attribution models define how credit for a conversion is distributed across the touchpoints the customer had with your brand before converting. This is essential for understanding which channel (SEO, Google Ads, social media, email) actually drives results.
The most common models are:
- Last click: 100% of the credit goes to the last channel before the conversion. Simple, but it ignores the entire journey that came before.
- First click: 100% of the credit goes to the channel that brought the user in for the first time. It values the top of the funnel.
- Linear: splits credit equally across all touchpoints.
- Position-based: 40% to the first touchpoint, 40% to the last, and 20% split among the ones in between.
- Data-driven: uses machine learning to calculate each channel's actual contribution (available in GA4 with sufficient data volume).
For SEO and GEO, the last-click model tends to underestimate the value of organic, because many journeys start with organic search but convert through another channel. Data-driven or position-based models are fairer for evaluating organic's real impact.