Special thanks to Chris Evans and the entire Search Discovery team for helping research this post.

We get this question all the time – why is my Adobe Analytics data different from the data I’m collecting in Google Analytics? There are a lot of obvious answers out there –actions may not be tagged in both platforms, Adobe automatically collects download and exit links, a Tag Management System may be used for one and not the other, etc – but we wanted to walk through some of the more technical reasons why even standard metrics as simple as visits, pageviews, and bounce rate will be different. And yes, these differences will occur even if both tools are deployed from the same Tag Management System!

Different algorithms for post-processing

Adobe and Google use very complex algorithms to calculate sessions, time spent, and many other simple and standard metrics within their platforms. They also use different methodologies when it comes to attributing these metrics to dimensions within the platform. Adobe even allows for additional customization depending on the variable type that allows for Most Recent, Original, Linear, and Participatory allocation.

Different visitor session length

The “end” of a session is always a very difficult event to capture in a web analytics platform. Since we cannot track browser window or tab closing actions nor website exits via URL address changes it is difficult to know the exact end of the session. Both platforms generally consider the end of a session to be the timestamp of the last tag called. Google has the ability to limit the effect it has on sessionization when an event is called using the optional “non-interaction” feature of the trackEvent method.

Different tracking libraries

Each platform uses completely different code libraries for tracking. This means that although they both aim to have perfectly infallible code, neither does. So other code on the page or injected via other tags on the site may affect the analytics code differently depending on the web analytics platform.

GA typically fires at the page top and Adobe at the page bottom

When it comes to website tracking, timing is everything. Google Analytics is generally called asynchronously at the top of the page (ie – in the <head> of the page). Adobe Analytics, however, is instead called synchronously at the bottom of the page. This often means that page views will get called at different times depending on how that page is coded. If there is script on the page that is of high priority and synchronous, then the Google Analytics code will wait for it and sometimes even wait until after the Adobe Analytics tag is called. However, since the GA tag usually lives at the top of the page it is often called before the Adobe tag. Finally, a pageview is sometimes so short that only one or neither tag will be called before the user clicks to the next page. This will unfortunately result in data loss since the pageview will not be captured by all platforms.

Different custom tracking methods

Although we often compare trackEvent() and s.tl() when teaching Adobe Analytics to GA users (or vice versa) they are not the same. They are clearly different in terms of the dimensions that can be tied to the metrics captured and the implementation of them is obviously different too. Adobe also has the option for a 500ms delay to ensure the image request isn’t aborted by browsers. Google unfortunately doesn’t have this, so differences in onClick tracking will result.

Different custom filtering methods

Adobe and Google both have the ability to adjust the data flowing into their platforms pre-processing. Google profiles have the concept of “Filters” whereas Adobe has “Processing Rules”. Both of these tool features are powerful and useful, but beware that they both have caveats. For example, Adobe Processing Rules cannot be used to move data from one report suite to another, whereas Google Filters can filter data to a specific View. In addition, Google Filters can also be applied to completely remove data from a specific View. There are more differences between capabilities, but it’s important to remember that these differences will affect change in data when comparing platforms.

Different bot lists

Adobe and Google both have bot filtering platforms. Unfortunately, this is a necessary requirement in analytics platforms these days as bots are getting smarter – running javascript, changing user-agents, and even refreshing IP addresses. Web analytics platforms are doing what they can to keep up, but there is no surefire way to remove that data. Adobe uses the IAB (Interactive Advertising Bureau) list of spiders and bots by default. These bots still send data to your report suite, but the data is filtered into the “Bots and Bot Pages” reports found in the Site Metrics folder. Google Analytics also subscribes to the IAB list and is enabled via the Reporting View Settings section of the admin console. In addition – both platforms allow for custom IP-based filtering. Adobe also allows bot filtering at the user agent level. Unfortunately, it’s a cat and mouse game for both platforms. As an analyst for a company that uses both platforms, be sure to keep your rules in sync.

Time Zone / Definition of End of Day

Time zone is one of those really subtle settings that you enable early on in the data capture process and forget about. Unfortunately, once you’re comparing data between platforms it can have a huge effect on data disparity. If Google Analytics is set to the Pacific Time Zone and Adobe is set to Eastern, then looking at data on the same day between platforms is guaranteed to be different. Time Zone is set in the View Settings for Google Analytics and the General Account Settings for report suites in Adobe.

In Summary

So as you can see – there is going to be some variance between your analytics platforms, but this is okay! Most of our customers that have both tools implemented are using Google Analytics as a backup system or simply because it integrates well for their media agency’s data. Search Discovery recommends defining one and only one system of record, one source of truth. This single system of record will always provide the best answer when answering questions; your backup data is just that – backup data. If you spend too much time comparing platforms, you’ll be missing out on the opportunity to take action on your data – and isn’t that the goal in the first place?