A complete analysis of the five reasons for the difference between GA4 and Google Ads data

In the 2023 shopping season, independent websites fully upgraded GA4 to cooperate with Google Ads for advertising and advertising effect measurement. Due to code errors, tool associations, attribution logic, counting mechanisms, and account configurations, large data discrepancies occurred, especially for independent websites that rely on GA Conversion Bidding , which seriously affected the delivery of advertisements. Solving the data discrepancy between GA4 and Ads is a necessary task before entering the shopping season. The reasons for the data discrepancy can usually be summarized into five categories. The frequency of our encounters with these five categories of problems is shown in the figure below.

It is recommended that all independent sites check data differences and try the following solutions

Code Problem

G A4 conversion code and Ads conversion code deployment issues

Check whether the website has correctly installed GA4 and Ads conversion codes, and whether there are multiple triggers, false triggers, or non-triggering in certain scenarios.

User preferences for different tracking methods

Check whether the website has set a cookie banner . If so, there may be users who have blocked GA cookies , then only conversions from ads will be tracked , and vice versa.

Tool association

Linking multiple GA4 accounts in Ads causes discrepancies

Check whether the conversion value viewed in Ads is aggregated from several conversion actions, and compare whether the conversion data viewed in Ads is aggregated from multiple GA4 conversion associations or Ads pixel codes .

Data discrepancies due to short association time

Ads conversion data will usually be displayed within 3 hours, and Ads conversions imported by GA will usually be displayed within 9 hours. Therefore, if the association time is short, it will lead to data differences. You can wait for a while before checking again.

The date range selected for viewing data is too long and involves unlinked account periods, resulting in discrepancies

Check the time period when Google Ads and GA4 were linked. If the data range you are comparing exceeds the unlinked time period, this will cause data discrepancies.

Attribution Problem

Data discrepancies due to attribution models

Check if the attribution model used in GA4 and Ads is consistent. It is recommended to use the conversion count or value corresponding to the source / medium dimension without any prefix in GA4 and check it with the one in Ads.

Data discrepancies due to attribution time

In Ads, the dimension without (by conv.time) records the conversion according to the ad click time, while GA4 records the conversion according to the ad conversion time by default. It is recommended to select the dimension with (by conv.time)to view the datawhen checking the difference between Ads and GA4 .

Counting Problem

Filters in GA4 cause data discrepancies

Check if there are filters set in GA4 that exclude certain data, but there are no filters set in Ads , resulting in data differences.

Google Ads ’ estimate conversions based on models feature

Check what specific metric fields you are viewing in Ads . Since Google Ads conversion tracking allows you to estimate cross-device conversions, the estimated results are displayed in the All conv. prefix metrics in Google Ads, while GA4 does not record this type of conversion.

The counting settings of GA4 conversions and Ads conversions cause discrepancies

Check whether the conversions are counted once or multiple times in GA4 and Google Ads respectively.

Account Settings

Discrepancies caused by incorrectly tagged parameters in the campaign or the landing page not firing the GA4 tag

Check whether the link parameters of the landing page are normal, that is, whether the automatic tagging is applicable to the website, and whether there is no redirection that causes the loss of gclid or utm . At the same time, check whether the landing page code can be triggered normally so that the landing page parameters can be obtained normally.

Account time zone settings cause data differences

Check whether the time zones set in GA4 and Ads are consistent. If the data range you view is too short, the time zone will cause data discrepancies.

Conversion action adjustments cause data discrepancies

Check if you switched one of your Google Ads conversion actions from Primary to Secondary within the viewing range .

The metrics prefixed with Conv. are calculated based on primary actions . The metrics prefixed with All conv. include not only primary actions but also secondary actions .

Other issues

If you still have other problems during use or troubleshooting, you can submit tickets to seek official help from Google.