Google Analytics and Ad Manager discrepancies

We recommend that you don't compare Google Analytics and Ad Manager numbers due to possible discrepancies. 

If you see significant discrepancies (>10%) between the reports in your Google Ad Manager account and those in Google Analytics, keep in mind these important points:

  • Analytics tracks page views while Google Ad Manager counts ad impressions. Be sure you compare reports that match the appropriate pages in Analytics with the proper slots in the Google Ad Manager reports.
  • Use the inventory reports in Google Ad Manager and segment by ad slots for the most precise comparison.
  • Activate the Unfilled impressions column to see if there are a significant amount of blank ads being served.
  • Verify that Google Ad Manager and Analytics code are both on the same page and in the proper locations within the HTML.
  • Make sure any customizations are consistent across all products, including Ad Manager, Google Analytics, and Google Tag Manager. For example, if you set a custom domain name for Google Analytics, the custom domain must be consistent with Ad Manager and set before the first GPT request.
  • To comply with new regulations, Google Analytics can use either TCF or Consent Mode, but the consent given to show an ad on a specific site will not be the same as the consent given on the landing page. This can explain the discrepancies between clicks on a publisher environment and a tracker on the landing page.
  • Google Analytics starts sampling after a specific number of hits is reached. This sampling can also explain the discrepancies.
  • Consider the passback scenario where Ad Manager serves a third party creative. When the third party system doesn't have an ad to serve, a passback tag is served back to Ad Manager. This results in a chain where:
    • 1) User lands on the page and sends a request to Ad Manager.
    • 2) Ad Manager returns a third party tag to the users page as the creative.
    • 3) The third party doesn't have any inventory to serve and falls back to returning a GPT passback tag to the page as the creative.
    • 4) The user's browser receives the GPT passback tag from the third party and makes another call to Ad Manager.
    • 5) Ad Manager serves an ad and records an impression.

      ​In this example, Google Analytics records 1 Page view metric and Ad Manager records 2 impressions, one from Step(2), one from Step (5). 

Even if your code is set up properly, statistics may still differ between Google Analytics and Google Ad Manager.

Ad impressions in Ad Manager versus pageviews in Google Analytics

There are a few reasons why an ad impression in Google Ad Manager may not equal a pageview in Google Analytics:

  • Separate JavaScript code: Google Ad Manager counts an impression (for display creatives) when the server responds with an ad response. Similarly, Analytics counts a pageview only when the Google Analytics tracking code is executed by a user's browser. Because they are located in different parts of your page, it is possible that one of these JavaScript snippets load and the other does not.

    If you've placed your Analytics code towards the end of your page, in very rare cases, a user enters and then exits a page before the page completely loads and before the tracking code is executed. In this case, Google Ad Manager might count an ad impression, but Analytics doesn't count the pageview. This would result in a higher impression count in Google Ad Manager than pageview count in Analytics.
  • Iframes: Some publishers have placed Google Ad Manager tags in an iframe to serve ads. Browsers that don't support the <iframe> tag don't report an impression. This can result in Analytics counting more pageviews than Google Ad Manager counts impressions.

    For browsers that do support iframe tags, putting the Google Ad Manager tags within an iframe can result in an extra round trip between the browser and server. This additional latency can cause some users to leave the page before the browser has enough time to make the calls to both Analytics and Google Ad Manager.

    • Security (blocking) Software: Your Google Ad Manager impressions might also be decreased by personal firewall software or ad blocking software which can cause Google ads to not display on your site, or may obscure portions of the ad. Ad blocking features of your users' internet security software must be disabled in order to view Google ads.
    • Time zone: If your Analytics timezone doesn't match your Google Ad Manager timezone, then the two sets of reports aggregate different time periods for the same displayed date. Learn how to set the time zone for your Google Analytics reports.
    • Analytics profiles: Analytics allows you to create different profiles that can be used to filter data. If you view a profile that filters out some data, then the Google Ad Manager data meant to correspond to the filtered-out data is not shown. Learn about how to create filters to control your report data.
  • Video Solutions companions: Google Analytics includes Video Solutions companion impressions, since they are display ads, but does not include Video Solutions ad impressions. When comparing impression totals, be sure to include Video Solutions companion impressions.

Comparison between ad impressions to pageviews

Here are a couple of items to keep in mind when you compare ad impressions to pageviews:

  • Frames: If the Analytics tracking code is present with a framed page as well as the framing page, Analytics registers two pageviews for that visit. This can result in inflated pageviews in Analytics. Learn more about framed sites.
  • _trackPageview function: If you're using the _trackPageview function, your pageviews may be slightly inflated within Google Analytics. The function _trackPageview creates virtual pageviews for specific events such as PDF downloads that aren't tracked in your Google Ad Manager account. Learn more about using virtual pageviews through Special Case Goals and Funnels.

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