Index and Overlap - Campaign

In this article

A guide to navigating Index and Overlap insights for Campaigns



Index and Overlap are a section of Campaign Insights that allow you to see which of your cohorts users you have targeted with a Google Ad Manager campaign fall into.

Note: Campaign insights are only available for PG deals that do not contain any video creative or third-party hosted creative

This data can be useful in post-campaign analysis once a campaign has wrapped up, or mid-campaign for campaign optimization.


At the top of the Index and Overlap insights dashboard you will see Campaign and Filter. If you click 'Edit' next to Campaign you can choose which Ad Manager campaign or campaigns for which you want to see index and overlap data.


If you click 'Edit' next to Filter, you will see the filters available to apply to the data.


 You can choose the date range, line item, domain, device, geolocation, and platform as well as whether you are looking at users who clicked on the campaign or viewed the campaign.


Tip:  If you get an error, please see this article for solutions: Common Insights Errors

To specify which cohorts you want to measure your selected campaign against you will need to select a base cohort as well as comparison cohorts.

  • Base Cohort - The base cohort is the base line or 'average user' that you want to index your campaign-targeted users against. You can only select one base cohort.

Note: Base Cohort only pertains to index and has no effect on overlap


Tip: Set the base cohort to 'Everyone' to see how much more likely users are to belong to a comparison cohort than all other users on your site.

  • Comparison Cohorts - Comparison cohorts will be the cohorts or tag groups that populate the list. Choose the cohorts for which you want to see the overlap and index of the users who interacted with the campaign or group of campaigns you selected. You can also click 'Select All Cohorts' to see how users targeted by your campaign compares to all cohorts you have created.


  • Minimum Uniques - If you set minimum uniques, the chart will only return comparison cohorts that meet that minimum. If a comparison cohort you selected do not meet the minimum, it will not appear in the chart regardless of the fact that it is selected.


Interpreting the Data


Once you have selected your campaign (GAM order ID), base cohorts and comparison cohorts you are ready to analyze the data.

In the example above, we are seeing how users who viewed Campaign 211706487 overlap with cohorts we have created, as well as how users who viewed the campaign index against them.


  • Overlap - Looking at Sport Enthusiats, we see a 52.51% overlap. This means that 52.51% of users who viewed campaign 211706487 fall into our Sport Enthusiats cohort.
  • Index - The index goes off a base of 100 and indicates that users who viewed campaign 211706487 are 56% or 1.56x more likely to be in the Sport Enthusiats cohort than average users are. 

If you need more clarity on reading the data, please see this article.

Downloading Data

To download the overlap and index report as a CSV file, click the download button in the upper righthand corner and select 'Download chart data'


If you have any questions, please contact customer support by emailing or chat to the Customer Operations Team via the LiveChat icon in the bottom right corner of your screen.



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