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Attribution Models: Who Gets Credit For The Conversion
Before converting, people often go through several channels. Your attribution model decides which one gets credit for the conversion. Build a 4-touchpoint path, choose where you read the conversion, Google Ads or Google Analytics 4, and compare last click with data-driven attribution.
In Google Ads, the help center describes two attribution models: last click, and data-driven, the default for most conversion actions. Google Analytics 4 offers three: data-driven attribution, paid and organic last click, and Google paid channels last click. The first click, linear, time decay and position-based models were retired in 2023.
Your Path And Last Click
Pick where you read the conversion and the channel of each touchpoint: the last click models apply the rules Google publishes.
- Conversion
Rules and examples from Google Ads help on attribution models and Google Analytics help on attribution, read on 15 October 2026. In Google Ads, the tool reads a conversion that credits Google paid channels: only your Google Ads ads can get credit there.
Data-Driven Attribution, As An Illustration
Google compares the paths of people who convert with the paths of people who don’t. Set the conversion chance with all 4 touchpoints, then without each one: the tool replays the principle Google publishes.
Principle and worked example from Google Analytics help on attribution, read on 15 October 2026. Google calculates on your account’s data, with other signals such as time to conversion, device or ad order, and does not publish how the increases become shares: here, they are proportional. Your own split shows in the “Model comparison” report in Google Ads.
How Google Splits The Credit For A Conversion
Last click: 100% to the last credited touchpoint Increase due to a touchpoint = chance with it ÷ chance without it - 1 Google’s example: 3% ÷ 2% - 1 = +50%
Last click gives all the credit to one touchpoint. In Google Ads, that is the last clicked ad, with its keyword. The example in Google Ads help follows a customer who searches “restaurant tuscany”, “restaurant florence”, “3 star restaurant florence”, then “3 star restaurant abigaille florence” before booking: with last click, that last keyword gets 100% of the credit.
Data-driven attribution compares the paths of customers who convert with the paths of customers who don’t. Google Analytics help shows it on 4 touchpoints: with all 4, the conversion chance is 3%; without the 4th, it goes down to 2%, so the 4th touchpoint drives +50%. Google repeats this for each touchpoint and uses those contributions as attribution weights. The total is always one conversion, split into fractions.
The second part of the tool replays that principle on chances you set yourself. Google applies it to your account’s data, with other signals: time to conversion, device, number of ad interactions, ad order, format. The share your account gives each touchpoint therefore shows in your account. While building the tool, I noted one point the help does not publish: exactly how those increases become shares. The tool makes them proportional, and says so.
What Each Model Counts
- Last click in Google Ads: all the credit goes to the last clicked ad and its keyword. The model is still available, and you set it in the settings of each conversion action.
- Data-driven in Google Ads: the model reads the interactions with your Search (Shopping included), YouTube, Display and Demand Gen ads, clicks and video engagements included. It works whatever your volume, and Google recommends at least 200 conversions and 2,000 ad interactions within 30 days for a more precise split.
- Paid and organic last click, in GA4: 100% to the last channel clicked through, or the last engaged view for YouTube. Direct visits are excluded, unless the path is only direct visits.
- Google paid channels last click, in GA4: 100% to the last Google Ads click. With no Google Ads click in the path, the model falls back to paid and organic last click.
- Credited channels and window: for a conversion based on Google Analytics, Google Ads credits Google paid channels by default, and GA4 credits paid and organic channels. In Google Ads, the click-through conversion window is 30 days by default, adjustable from 1 to 90 days depending on the source; in GA4, the lookback window is 90 days by default, and 30 days for first_visit and first_open.
Frequently Asked Questions
Which attribution model should I choose in Google Ads?
Data-driven is the default model for most conversion actions: it uses your account’s data to calculate the contribution of each interaction. Last click is still available. The choice also matters for your bids: Target CPA and Target ROAS optimize for conversions as the model counts them. Before you switch to a model other than last click, Google recommends testing it and assessing how it affects your return on investment, for example with the “Model comparison” report.
What happened to first click, linear and position-based attribution?
Google announced their removal on April 6, 2023, along with time decay: in Google Ads, no new selection starting in June 2023, then conversion actions still using them switched to data-driven attribution starting in September 2023. Google Ads help now confirms those actions use data-driven attribution. In Google Analytics 4, those models are no longer available as of November 2023. Last click is still available in both tools.
Why don’t Google Ads and Google Analytics show the same conversions?
They don’t credit the same channels. For a conversion based on Google Analytics, Google Ads credits Google paid channels by default, while Google Analytics reports credit paid and organic channels: a sale after a Google Ads click and then an organic visit is filed in a different place. The model you pick, the conversion window and each tool’s time zone add to the gap. Google Analytics help suggests comparing with the “All conv.” column in Google Ads.
Does data-driven attribution need a minimum volume?
All conversion actions can use it, whatever their volume. Google recommends at least 200 conversions and 2,000 ad interactions within 30 days so the model can identify patterns better. Depending on data availability, the help notes that last click and data-driven attribution can have the same results in certain situations.
Are Your Bids Crediting The Right Channels?
The attribution model of your conversion action decides which campaigns get the credit, and so what your Target CPA and Target ROAS optimize for. The “Model comparison” report shows, campaign by campaign, what each model gives them.
Invest In The Right Channels
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