Reporting discrepancies are common and expected when multiple systems measure line item delivery.
For best results, investigate discrepancies while a line item is running. Fewer troubleshooting steps are available after a campaign ends.
Before you begin investigating
Verify that both reports:
- Cover the same date range, using the same time zone.
- Include the same line items or ads.
- Exclude unfilled impressions, as these can inflate Ad Manager numbers.
When an ad server delivers line items hosted by a third party, reporting discrepancies between the two systems occur, and campaign variances of up to 20% are common.
The following list contains common causes for discrepancies in third-party reports.
- Incorrect Ad Manager creative setup: To accurately track events, click-trackers and other macros must be properly implemented. Contact your creative developer, advertiser, or third-party for guidance.
- Impression counting differences: Ad servers have different methods for counting impressions and filtering invalid impressions. Learn how Ad Manager counts impressions.
- Different geography definitions: Different ad servers map IP address location data differently, which can lead to significant discrepancies.
- Latency: Lag between an initial line item request and the appearance of the creative can lead to different counts. For instance, a user often navigates away after the browser receives the Ad Manager line item request but before the third party responds with the requested line item, or a user may click on a link but navigate elsewhere before the landing page loads.
- Network connection and server reliability: A third-party ad server may fail briefly or encounter an issue that prevents it from logging an impression.
- Ad blockers: Ad blocking software can prevent the line item from being delivered by the third party after Ad Manager has already counted an impression.
- Low impression goals: A small numerical discrepancy can cause a high percentage discrepancy if the line item delivered few total impressions. For example, if you have a campaign delivering 100 impressions per day, a single-day discrepancy of 30 impressions leads to a single-day discrepancy of 30%, even though the actual number of missed impressions is low.
- Passbacks and calls to other third-party servers: Each third-party ad server can lead to campaign variances of up to 20%. If one third-party server points to yet another third-party server, the expected discrepancy increases.
- Third-party day/time targeting: Day- or time-targeting on the third-party ad server can lead to Ad Manager counting an impression when the third party doesn't return a creative.
- Third-party frequency capping: A third-party frequency cap can prevent an ad request from being filled, even if Ad Manager has counted an impression.
- Multi-use creatives: Has the third party ensured that no other publishers received the same tags?
Learn more about discrepancies between Google Analytics and Ad Manager.
If you're working with Campaign Manager 360 creatives, make sure you use the "Campaign Manager 360 tag" creative type. With this creative type, Ad Manager coordinates impression counting to reduce discrepancies within 2%.
If you traffic a Campaign Manager 360 creative tag using any other creative type, such as "Custom" or "Third-party," expect discrepancies up to 20%. For troubleshooting, refer to "Why third-party reports might differ" above.
- Creative reassignment: Have you or the advertiser made any changes during the time in question, such as reassigning or modifying creatives?
- Creative code issues: Does the advertiser code load properly? To verify that the correct ad tag calls are being made, perform live tests on web pages where the line item should deliver.