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Google Ads Attribution Models Explained

Attribution models determine how credit for conversions is distributed across the touchpoints in a customer's journey. Google Ads offers data-driven attribution (recommended default, uses machine learning to assign credit), last click (all credit to the final click), first click (all credit to the f

Optimisation & Reportinggoogle ads attribution models

Quick Summary

Attribution models determine how credit for conversions is distributed across the touchpoints in a customer's journey. Google Ads offers data-driven attribution (recommended default, uses machine learning to assign credit), last click (all credit to the final click), first click (all credit to the first interaction), linear (equal credit to all touchpoints), time decay (more credit to recent touchpoints), and position-based (40% to first and last, 20% distributed among middle). Data-driven is recommended for accounts with enough conversion volume.

Process Flow

Interactive diagram — drag to pan, scroll to zoom

Step-by-Step Guide

Follow these 4 steps to complete this guide

1

Why Attribution Matters

Most customers do not convert on their first interaction with your brand. They may see a Display ad, search your brand name later, click on a Shopping ad, and finally convert through a Search ad. The attribution model you choose determines which of these touchpoints gets credit for the conversion — and therefore where your budget appears most effective.
2

Data-Driven Attribution (DDA)

Google's recommended model. It uses machine learning to analyse your actual conversion paths and assign fractional credit based on how much each touchpoint contributed. Requires roughly 300 conversions in the past 30 days to work effectively. If your account qualifies, always use this model.
3

Other Models

Last click: 100% credit to the last-clicked ad. Simple but ignores the role of awareness and consideration touchpoints.

First click: 100% credit to the first interaction. Overvalues top-of-funnel but useful for understanding which channels introduce new customers.

Linear: Equal credit across all touchpoints. Fair but does not reflect the actual influence of each interaction.

Time decay: More credit to touchpoints closer to the conversion. Reasonable for most businesses but still a simplification.

Position-based: 40% to first touch, 40% to last touch, 20% split among the middle. A balanced option if DDA is not available.

4

How to Change Your Attribution Model

Go to Goals > Conversions > select the conversion action > Edit settings > Attribution model. Changes apply prospectively — historical data is not recalculated.

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