Attribution Model
A framework for assigning credit to marketing touchpoints along the customer journey that lead to a conversion. Common models include first-touch, last-touch, linear, time-decay, position-based (U-shaped), and data-driven. The formula varies by model: linear divides credit equally, time-decay weights recent interactions more heavily using an exponential decay function, and position-based typically assigns 40% to first and last touch with 20% distributed across middle interactions. Google deprecated last-click as the default in GA4 in favor of data-driven attribution.
Why It Matters
The attribution model you choose fundamentally changes how you evaluate channel performance and allocate budget. Research shows switching from last-click to data-driven attribution can shift up to 30% of budget recommendations across channels. Different models can make the same channel appear either highly effective or nearly worthless, making model selection a critical strategic decision that directly impacts media mix decisions, team KPIs, and ultimately revenue growth.
Example
A customer clicks a Facebook ad, then a Google search ad, then converts via an email link on a $150 purchase. First-touch gives 100% credit to Facebook, last-touch gives 100% to email, linear splits credit at $50 each, and position-based assigns $60 to Facebook, $30 to Google, and $60 to email. After switching from last-touch to position-based, the marketing team reallocated 15% of budget to upper-funnel social campaigns, increasing new customer acquisition by 22%.
Related Terms
First-Touch Attribution
An attribution model that gives 100% of the conversion credit to the first marketing touchpoint a customer interacted with. It is useful for understanding which channels drive initial awareness and demand generation. The model is calculated simply: the channel or campaign that initiated the first tracked interaction receives full credit. First-touch is especially popular among B2B marketers where the average buying cycle spans 6 to 12 months, making it important to identify which channels fill the top of the pipeline.
Last-Touch Attribution
An attribution model that assigns all conversion credit to the final touchpoint before a customer converts. It is simple to implement and easy to verify since only the closing interaction is tracked, but it systematically undervalues earlier interactions in the journey. Last-touch was the default in Google Analytics Universal and remains common in many CRM systems. With average e-commerce journeys involving 4 to 8 touchpoints, last-touch ignores up to 87.5% of the customer path.