This post was updated on September 21, 2017, for accuracy.
We get this question all the time: “Why is my Adobe Analytics data different from the data I’m collecting in Google Analytics?”
In this post, we will explore the most common drivers of those differences. When properly implemented, neither platform is “right” or “wrong.” They’re simply “different.” Understanding the drivers of those differences, hopefully, will allay the concerns of you and various concerned stakeholders.
Quantifying the Difference
Before diving into understanding why the two platforms provide different results, it’s worth getting a really good understanding of how much and how consistently they differ. This can be done with any number of platforms, but, if you do not have your Google Analytics and Adobe Analytics data feeding into a common system somewhere, you may need to simply resort to Excel or Google Sheets. This Excel template can be used as a starting point. It will generate the charts below using the data you plug into it.
In the example above, both platforms generally move pretty consistently with each other, with Adobe Analytics consistently being just a few percentage points below Google Analytics. The exception, in this case, was a week when Google Analytics disappeared from the site. Finding this sort of issue, as well as having some “backup data” to work with, is one reason that you may want to have a primary platform implemented as well as a secondary platform.
But, generally, in the above example, the data tracks pretty similarly, but not exactly the same. This is to be expected, as we’ll discuss below.
So, What Is Driving the Differences?
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, below, we walk through some of the more technical reasons why even simple, standard metrics like 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 will also close your session earlier than Adobe if it detects UTM parameters in the URL, or if the referring domain has not been added to your referral exclusion list.
Google analytics typically fires at the page top and Adobe at the page bottom
When it comes to website tracking, timing is everything. The Google Analytics pageview is generally called asynchronously at the top of the page (i.e. in theof 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 a 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, if a user navigates quickly through your site it is possible 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 Google Analytics events to 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.
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
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.
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 with their data. We strongly recommend 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, and 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. Isn’t that the goal in the first place?
If you have any questions or would like to discuss how we can help you dig into your data further, feel free to contact us. We would love to chat!