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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, the 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 AdWords. 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 is not available for interactions with Display Network ads. It’s only available for website, Google Analytics, and import conversion actions, not for app, phone call, and in-store conversions.

Benefits

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. But 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

AdWords offers several attribution models:

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

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.)

Example

You own the Hotel Paulina in Florence, Italy. A customer finds your site by clicking on your AdWords 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 special 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. For instructions, see How to set an attribution model for your conversions below.

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 CPA, Enhanced cost-per-click (ECPC), or Target ROAS, the attribution model you select will affect how your bids are optimized. Note that for Shopping campaigns, while your attribution models will be reflected in your conversions reporting columns, Shopping bid strategies will bid based on last click attribution.

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.

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 cost-per-acquisition (CPA) and return on ad spend (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.

To find Attribution Modeling, follow the steps below:

  1. Sign in to your AdWords account.
  2. Click the Tools tab, then select Attribution.
  3. In the menu on the left, click Attribution modeling.
  4. Select the dimension for which you want to view attribution models: Campaign, Ad group, or Keyword.
  5. Click 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.

For manager accounts (MCC), follow these steps:

  1. Sign in to your AdWords manager account.
  2. In the menu on the left, click Attribution.
  3. Follow steps 3 through 5 above.

How to 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 change the attribution model for an existing conversion action:

  1. Sign in to your AdWords account.
  2. Click the Tools tab and select Conversions.
  3. In the table, select the conversion action you want to edit, and then click Edit settings.
  4. Click on Attribution model, and select an attribution model from the drop-down menu.
  5. Click Done, and then click Save.

Note: 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. To change an attribution model in a manager account:

  1. Sign in to your manager account.
  2. Click the Accounts tab.
  3. In the menu on the left, select Conversions.
  4. In the table, select the conversion action you want to edit, and then click Edit settings.
  5. Click on Attribution model, and select an attribution model from the drop-down menu.
  6. Click Done, and then click Save.

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,” and will include cross-device conversions if you include them in your “Conversions” column. 

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

To add these columns to your reports, follow these instructions:

  1. On the "Campaigns" tab, click the Columns button and select Modify columns.
  2. In the left menu, click Attribution.
  3. You'll see a list of columns that you can add to your data table. Select the data you'd like to include.

Conversion data in Attribution reports vs. Campaigns tab

There may be differences in conversion data between your Attribution reports and the Campaigns tab. 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 tab 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 tab:

  Attribution reports Campaigns tab
Time of event Date of conversion Date of ad click
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 and shopping, and for Display if opted in

Time of event

The Campaigns tab shows conversions using the time and date of 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 a customer makes a purchase on July 20, after clicking on an ad three days earlier, on July 17. In the Campaigns tab, the conversion would be attributed to July 17, the day of the click. In Attribution reports, the conversion would be attributed to July 20, the day of the conversion.

Network

Data in the Attribution reports is limited to Search traffic only, while data in the Campaigns tab 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 tab, but aren’t available in the Attribution reports. For Attribution reports, only web site 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 tab, 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 tab, the “Conversions” column includes cross-device conversions for Search and Shopping, and for Display if opted in. 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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