Attribution model

Common models

• Last click: all credit to the final touchpoint before conversion. Simple; undervalues channels that create demand.
• First click: all credit to the first touchpoint. Highlights discovery; ignores what closed the sale.
• Linear: equal credit to every touchpoint.
• Time decay: more credit to touchpoints closer to conversion.
• Position-based: most credit to first and last touchpoints, the rest shared.
• Data-driven: algorithmic credit based on observed paths — the default in GA4 and Google Ads, where data volume allows.

Why it matters

The model changes reported ROAS and cost per acquisition by channel, and therefore budget decisions. Last-click models tend to favour search and remarketing; awareness channels such as social video appear weaker than they are.

Limitations

• Only tracked touchpoints count — offline conversations, word of mouth and untracked messenger contacts are invisible.
• Cross-device journeys and privacy restrictions reduce visibility.
• Platforms each claim credit using their own view, so totals across platforms exceed actual sales.

Using attribution wisely

• Choose a primary model and report consistently.
• Compare models to understand each channel's role.
• Use incrementality tests (holdouts, geo tests) for big budget decisions.
• Reconcile with actual sales in the CRM. See end-to-end analytics.