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 optimise across the user's conversion path.
This article describes the various attribution models and how to use them in Google Ads. You'll find out how to set an attribution model for conversion tracking and bidding, and how to compare models with 'Attribution Modelling' in your attribution reports.
Bear in mind
Attribution modelling 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: Optimise 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: 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: Gives all credit for the conversion to the first-clicked ad and corresponding keyword.
Linear: Distributes the credit for the conversion equally across all clicks on the path.
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: 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: 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 Modelling” report if you have adequate data in your account.
To learn how to compare these attribution models and see how they'd affect your data, see the section on the Attribution Modelling report below.
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 that customers clicked on 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 optimises for conversions, such as Target CPA, Enhanced cost per click (ECPC) or Target ROAS, the attribution model that you select will affect how your bids are optimised.
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 Modelling 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 cost per action (CPA). Learn more about how to change bids and targets after switching from last-click to data-driven attribution
“Attribution Modelling” 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: Analyse your CPA or ROAS for different attribution models
You can use Attribution Modelling to compare your cost per acquisition (CPA) and return on ad spend (ROAS) for different attribution models. This allows you to identify campaigns or keywords that 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.
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
- Sign in to your Google Ads account.
- In the upper right corner of your account, click the tools icon , then under 'Measurement', select Search attribution.
- In the page menu on the left, click Attribution Modelling.
- Click Campaign to select one of the following: Campaign, Ad group or Keyword.
- Click Last click to compare: Last click, First click, Linear, Time decay or Position-based.
- Use the drop-down menus to select the attribution models that 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
- Sign in to your Google Ads account.
- In the upper right corner of your account, click the tools icon , then under 'Measurement', select Conversions.
- In the table, select the conversion that you want to edit by clicking on the conversion name.
- Click Edit settings.
- Click on Attribution Model, and select an attribution model from the drop-down menu.
- Click Save, then click Finished.
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.
When you change the 'Attribution model' setting for a conversion action, it only changes the way that your conversions are counted in your 'Conversions' and 'All conversions' columns going forwards. If you want to see how your historic conversions data would look with the attribution model that 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've differed if you'd been using the attribution model that 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.
Bear in mind that these columns include data that isn’t affected by your attribution model selection, such as data from the Display Network.
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 optimise 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, shop 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 Campaigns page shows conversions using the time and date of the impression prior to the click that led to the conversion, rather than the date of the conversion itself. This allows you to match the value generated to the right advertising cost.
Let’s say that a customer makes a purchase on 20 July after clicking on an ad three days earlier, on 17 July. In the Campaigns page, the conversion would be attributed to 17 July, the day of the impression preceding the click. In Attribution reports, the conversion would be attributed to 20 July, the day of the conversion.
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. Bear in mind that traffic on these networks can only be reported on a last-click basis.
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 shop 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.
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.