About attribution models

On the path to a conversion, a customer may do multiple searches and interact with multiple ads from the same advertiser. Attribution models let you choose how much credit each click gets for your conversions. You can attribute the credit to the customer's first click, last click, or a combination of multiple clicks.

Attribution models can give you a better understanding of how your ads perform and can help you optimize across the user's conversion path.

This article describes the various attribution models and how to use them in Google Ads. You'll learn how to set an attribution model for conversion tracking and bidding, and how to compare models with "Attribution Modeling" in your attribution reports.

Keep in mind

Attribution modeling is only available for clicks on Search Network and Shopping ads on google.com, and isn't available for interactions with Display Network ads. It’s only available for website, Google Analytics, phone call, and import conversion actions, not for app and in-store conversions.


Most advertisers measure the success of their online advertising on a "last click" basis. This means they give all the credit for a conversion to the last-clicked ad and corresponding keyword. However, this ignores the other clicks customers may have made along the way.

Attribution models give you more control over how much credit each ad and keyword gets for your conversions. This allows you to:

  • Reach customers earlier in the purchase cycle: Find opportunities to influence customers earlier on their path to conversion.
  • Match to your business: Use a model that works best for how people search for what you offer.
  • Improve your bidding: Optimize your bids based on a better understanding of how your ads perform.

About the different attribution models

Google Ads offers several attribution models:

Last click Last click: Gives all credit for the conversion to the last-clicked ad and corresponding keyword.

When using the last click model, you might notice a slight time lag between what's reported in the "Conversions (current model)" column and the "Conversions" column for recent time periods. This lag eventually corrects itself.

First click First click: Gives all credit for the conversion to the first-clicked ad and corresponding keyword.

Linear Linear: Distributes the credit for the conversion equally across all clicks on the path.

Time decay Time decay: Gives more credit to clicks that happened closer in time to the conversion. Credit is distributed using a 7-day half-life. In other words, a click 8 days before a conversion gets half as much credit as a click 1 day before a conversion.

Position-based Position-based: Gives 40% of credit to both the first- and last-clicked ads and corresponding keyword, with the remaining 20% spread out across the other clicks on the path.

Data-driven Data-driven: Distributes credit for the conversion based on past data for this conversion action. (This is only available to accounts with enough data.)


You own the Hotel Paulina in Florence, Italy. A customer finds your site by clicking on your ads after performing each of these searches: "hotel tuscany," "hotel florence," "3 star hotel florence," and then "3 star hotel paulina florence." She makes a reservation after clicking on your ad that appeared with "3 star hotel paulina florence."

  • In the "Last click" attribution model, the last keyword, "3 star hotel paulina florence," would receive 100% of the credit for the conversion.
  • In the "First click" attribution model, the first keyword, "hotel tuscany," would receive 100% of the credit for the conversion.
  • In the "Linear" attribution model, each keyword would share equal credit (25% each) for the conversion.
  • In the "Time decay" attribution model, the keyword "3 star hotel paulina florence" would receive the most credit because it was searched closest to the conversion. The "hotel tuscany" keyword would receive the least credit since it was the earliest.
  • In the "Position-based" attribution model, "hotel tuscany" and "3 star hotel paulina florence" would each receive 40% credit, while "hotel florence" and "3 star hotel florence" would each receive 10% credit.
  • In the "Data-driven" attribution model, each keyword would receive part of the credit, depending on how much it contributed to driving the conversion.

Note: Data-driven attribution

Advertisers with sufficient data have access to a 6th attribution model: data-driven attribution. This powerful model distributes credit for the conversion based on observed data for this conversion action. It’s different from the other models, in that it uses your account’s data to calculate the actual contribution of each keyword across the conversion path.

You’ll only see this option in your “Attribution model” setting and in your “Attribution modeling” report if you have adequate data in your account.

Learn more about data-driven attribution

To learn how to compare these attribution models and see how they'd affect your data, see the section on the Attribution Modeling report below.

About attribution models for conversions and bidding

The "Attribution model" setting in conversion tracking lets you decide how to attribute conversions for each conversion action. You can use this setting for website and Google Analytics conversion actions. Learn how to set an attribution model for your conversions

This setting affects how conversions are counted in your "Conversions" and "All conversions" columns. (Keep in mind that the “Conversions” column only includes those conversion actions you’ve chosen to include with the “Include in ‘Conversions’” setting.) For example, if you choose “First click” as your attribution model, conversions will be credited to the first ad customers clicked before completing a conversion. In your reports, the conversions would count in the campaigns, ad groups, ads, and keywords associated with the first-clicked ad.

The attribution model you choose only affects the conversion action to which it’s applied, and only affects your Search Network and Shopping data. Display Network conversions and app and phone call conversions will still be attributed to the last click.

The setting also affects any bid strategies that use the data in the “Conversions” column. This means that if you use an automated bid strategy that optimizes for conversions, such as Target cost per action (CPA), Enhanced cost-per-click (ECPC), or Target return on ad spend (ROAS), the attribution model you select will affect how your bids are optimized.

If you use manual bidding strategies, you can change your attribution model to help you set your bids.

If you’re not sure what model to choose, see the section below on the Attribution Modeling report, which lets you compare different attribution models. When you’re trying a new non-last-click attribution model, it’s recommended that you test the model first and see how it affects your return on investment.

Note: Changing your attribution model from last-click to data-driven attribution (DDA) helps determine which of your clicks or keywords are most impactful. DDA assigns a value to each click and keyword that has contributed to the conversion process and helps drive additional conversions at the same CPA. Learn more about how to change bids and targets after switching from last-click to data-driven attribution

About the Attribution Modeling report

“Attribution Modeling” in your attribution reports lets you compare 2 different attribution models side-by-side. To find keywords, ad groups, or campaigns that are undervalued on a last-click basis, you can start with the following comparisons, for example:

  • Compare the “Last click” model to the “First click” model to identify undervalued keywords that are starting customers down the conversion path. This is particularly valuable if you’re looking to drive more new customers to your website.
  • Compare the “Last click” model to the “Linear” model to identify undervalued keywords that are assisting customers all along the conversion path. This is particularly valuable if you want to stay in touch with customers throughout their purchase process.

Tip: Analyze your CPA or ROAS for different attribution models

You can use Attribution Modeling to compare your CPA and ROAS for different attribution models. This allows you to identify campaigns or keywords which are undervalued using a last-click attribution model. You can then change your bids based on the actual value of your campaigns and keywords across the full conversion path.

How to find and set an attribution model for your conversions

You can set the attribution model when you're setting up your conversion action, or follow the instructions below to compare attribution models and change the attribution model for an existing conversion action:

Compare attribution models

  1. Sign in to your Google Ads account.
  2. In the upper right corner of your account, click the tools icon , then under “Measurement,” select Search attribution.
  3. In the page menu on the left, click Attribution Modeling.
  4. Click Campaign to select one of the following: Campaign, Ad group, or Keyword.
  5. Click Last click to compare: Last click, First click, Linear, Time decay, or Position-based.
  6. Use the drop-down menus to select the attribution models you want to see and compare. You can search for specific keywords, ad groups, or campaigns from the search box above the table.

Change the attribution model for an existing conversion action

  1. Sign in to your Google Ads account.
  2. In the upper right corner of your account, click the tools icon , then under "Measurement," select Conversions.
  3. In the table, select the conversion you want to edit by clicking on the conversion name.
  4. Click Edit settings.
  5. Click on Attribution Model, and select an attribution model from the drop-down menu.
  6. Click Save, and then click Done.

Cross-account conversion tracking

If you use cross-account conversion tracking to track conversions at the manager account level, you must select your attribution model in the manager account.

Attribution models in your reporting columns

When you change the “Attribution model” setting for a conversion action, it only changes the way your conversions are counted in your “Conversions” and “All conversions” columns going forward. If you want to see how your historic conversions data would look with the attribution model you’ve just selected, you can use the “current model” columns:

  • Conversions (current model)
  • Cost/conv. (current model)
  • Conv. rate (current model)
  • Total conv. value (current model)
  • Conv. value/cost (current model)
  • Conv. value/click (current model)
  • Value/conv. (current model)

These columns can be helpful if you’ve just changed your attribution model, and you want to get a sense of how it will affect your conversions data. You can compare these columns to your regular conversion tracking columns to see how your data would have differed if you had been using the attribution model you’ve now selected.

Like the regular “Conversions” columns, these columns won’t include any conversion actions that you’ve chosen not to include in “Conversions.” However, cross-device conversions are included by default.

Keep in mind that these columns include data that isn’t affected by your attribution model selection, such as data from the Display Network.

Conversion data in Attribution reports vs. Campaigns page

There may be differences in conversion data between your Attribution reports and the Campaigns page. This is due to differences in how conversions are counted across networks, time of event, conversion sources, and devices.

Attribution reports can help you estimate how changes to your attribution model might impact conversion reporting. Conversions in the Campaigns page can help you evaluate and optimize performance after you’ve changed your attribution model. You can also see past performance in Attribution reports by using the “current model” columns. For a more detailed overview of how this type of reporting works, read About attribution reports.

If you’re using conversion tracking from a manager account, we recommend that you use the Attribution reports in the manager account, rather than in the managed accounts.

How reporting varies

Here’s how conversions are reported differently in Attribution reports vs. the Campaigns page:

  Attribution reports Campaigns page
Time of event Time of conversion Time of the impression preceding the click that led to conversion
Network Google Search Network traffic Search (including Search partners), Display, YouTube
Conversion source Conversions on advertiser website, phone number click conversions, imported goals/transactions from Analytics, and imported off-line conversions. All sources including offline conversions, app conversions, store visits, etc.
Cross-device conversions Cross-device conversions are only included in “Cross-Device Activity” reports. All other Attribution reports exclude these conversions. The “Conversions” column includes cross-device conversions for Search, Shopping, and the Display Network.

Time of event

The primary conversion columns on the Campaigns page show conversions based on the time of the click, not the time of the conversion.

For example, if your ad was clicked last week and that traffic converted this week, both the click and the conversion are reported back to the last week in the primary conversions columns. This allows you to accurately measure metrics such as cost per conversion or return on ad spend, as ad spend is also calculated based on the time of the click.


Data in the Attribution reports is limited to Search traffic only, while data in the Campaigns page will include Search partner traffic, as well as Display or YouTube conversions. Keep in mind that traffic on these networks can only be reported on a last-click basis.

Conversion source

Certain conversion sources are supported in the Campaigns page, but aren’t available in the Attribution reports. For Attribution reports, only website conversions, phone number clicks conversions, and imported Analytics goals/transactions are counted. Other sources such as app conversions and store visits aren’t counted by Attribution reports. Imported offline conversions are compatible with Attribution reports. It’s recommended to upload conversions every 1-2 days. Conversions must be at most 7 days old when uploaded. In the Campaigns page, these other sources are tracked, but can only be reported on a last-click basis.

Cross-device conversions

These conversions come from customers who’ve signed into Google across different devices. In the Campaigns page, the “Conversions” column includes cross-device conversions for Search, Shopping, and the Display Network. In Attribution reports, you can only find cross-device conversions in the “Cross-device activity” reports. Learn more about cross-device activity reports.

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