In short. Google Ads attribution models allocate conversion credit across eligible ad interactions, with conversion windows and channel settings defining the reporting scope.

Definition: Advertising conversion attribution assigns credit for a measured business action, such as a purchase, to advertising interactions associated with it. An attribution model determines how that credit is distributed across the interactions leading to the action.

As of 17 October 2026, Google's conversion measurement guide describes conversions as actions an advertiser values, including purchases, sign-ups and phone calls. A conversion action is the specific customer activity configured for measurement. This entry covers Google Ads attribution settings for website and Google Analytics conversion actions, including outcomes associated with Search campaigns.

Key facts

Google's attribution model documentation describes last-click and data-driven attribution; data-driven is the default for most conversion actions.
Google's data-driven attribution guide covers website, store visit and Google Analytics conversions from Search ads, including Shopping, alongside other supported ad networks.
Google's conversion window documentation gives Search and Display campaigns a default window of 30 days when the advertiser leaves that setting unchanged.

How do the models allocate credit?

Google's model documentation defines last-click attribution as assigning all conversion credit to the last-clicked ad and its corresponding keyword. Data-driven attribution distributes credit using past data for the particular conversion action.

Google's data-driven guide explains that the model compares paths of customers who convert with paths of customers who do not. It identifies patterns among ad interactions and allocates more credit to interactions associated with a higher probability of conversion. Each advertiser has a model based on its own conversion data. Google also notes that last-click and data-driven attribution can produce the same results in some situations, depending on data availability.

Which channels can receive credit?

A creditable channel is a channel eligible to receive conversion credit. Google's attribution documentation lists distinct channel settings: under “Google paid channels,” Google Ads channels can receive credit; under “Paid and organic channels,” both paid and organic channels can receive credit.

The same documentation places this information alongside the “Attribution model” setting. Conversions configured through different Google products can have different creditable channels. Reading the model together with that channel setting establishes which interactions are eligible to share the reported outcome.

How does the conversion window affect outcomes?

Google's conversion window guide defines the window as the period after an ad interaction during which a conversion is recorded. The window belongs to the conversion action and can be configured separately for different actions.

The guide gives a promotion example with a 7-day window: a conversion happening more than 7 days after the interaction is excluded from reporting. This setting therefore determines which outcomes enter the conversion totals before their credit is interpreted through an attribution model. The guide directs advertisers to the time lag report in attribution reports when choosing a window that fits the time customers take to convert.

How can the settings be checked?

Google's model comparison instructions give this report path:

Goals > Attribution > Model comparison

The report compares models side by side. Its “Dimension” selector supports examining campaigns, ad groups or keywords, while “Compare” and “With” select the models. For an existing conversion action, the same documentation directs advertisers to Summary in the Goals menu, then the conversion name, “Edit settings” and “Attribution model.”

The selected model affects that action's “Conversions” and “All conversions” reporting. The “Conversions” column includes actions marked as primary conversions, and bid strategies using that column also use the resulting attribution data.

FAQ

Does changing the model rewrite historical conversion columns?

Google's attribution documentation says the change applies to the regular conversion columns going forward. You can add “current model” columns to examine historical conversions under the selected model.

Is data-driven attribution available with few conversions?

Google's data requirements make all conversion actions eligible regardless of conversion or interaction volume. The guide says model performance improves with more data.

Can I select first-click attribution in Google Ads?

Google's attribution documentation lists first-click, linear, time-decay and position-based models as no longer supported. Actions previously using those models move to data-driven attribution, and last-click remains available.

Sources

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