Session vs. User Based Tracking in Google Analytics

by | Aug 30, 2020 | Ecommerce, Google Analytics | 0 comments

Not sure which is better to use for benchmark metrics – Sessions or Users?

Trying to work out why Google Analytics is reporting different conversion data than another platform e.g. Shopify Analytics or Facebook Campaign Manager?

Or are do you want to combine ecommerce stats that are in your sales CMS with Google Analytics Engagement and Acquisition data to gain insights in to customer loyalty?

It is all to do with the way data is collected and the available categorisations at the time of data collection.

An out-of-the-box Google Analytics implementation is limited. I always cringe when I am asked to do analysis work on an account that I haven’t previously audited, cleaned up and enhanced with Custom Dimensions, Metrics or Events (which are even more important now because of things like ITP2).

Lets start with introducing a few key concepts and definitions…


Sessions in Google Analytics

Google Analytics tracks site visitors based on Sessions.

The sessions metric reported in Google Analytics is the total number of Sessions within the specified date range.

A Session is the period of time a user is actively engaged with your website, app, etc. All usage data (Screen Views, Events, Ecommerce, etc.) is associated with a session.

Users that leave your site and return within 30 minutes are counted as part of the original session.


Users in Google Analytics

The Users metric in Google Analytics is the total number of Users who have initiated at least one Session during the date range.

By default Google Analytics does not have a very good way of measuring Users. They use something that is a called Client ID to define a user.


Client ID in Google Analytics

The Client ID is a unique, randomly generated string that gets stored in the browser’s cookies, so subsequent visits to the same site can be associated with the same user.

You can see how this is troublesome if:

  • The cookies have been cleared
  • Safari is the browser – because of Apple’s ITP2 protocol (ITP = Intelligent Tracking Prevention).
  • The visitor accesses your website from different devices/browsers.



Users vs. Sessions in Google Analytics

So how do these compare to each other?

Side by side:

  • Users: Unique visitors – or an actual person that has visited your website.
  • Sessions: Unique visits – or different times that person came to your site. One User can have multiple Sessions associated with it.


User ID in Google Analytics 

Next is User ID… User ID (or Customer ID) is a unique identifier that is assigned by your CMS backend sales software to users who have an account, i.e. customers on an ecommerce store.

This value is not sent to Google Analytics by default.

It is an enhancement that needs to be specifically set up.

You will need to define a User ID variable in the UA tracking script or your sites dataLayer in order to make it available for Google Analytics to read.


The User ID View in Google Analytics

Google Analytics has a built in feature that if a User ID is defined in the analytics tracking script then you can set up a User ID View (from the property settings menu).

Once it is configured, the Client ID is replaced by the User ID/Customer ID in populating the value that defines the Users metric, thus making it more accurate and meaningful.

This value is only assigned IF the site visitor logs into their account during the session or a Customer ID is generated from a transaction.

In the case of most ecommerce sites this happens during the checkout process (if they have not yet already logged in – as long as it is not an anonymous guest checkout).

The User ID is exposed for Google Analytics to record. If they do not log in then there is obviously no way to know their User ID.

The User ID View is not the most amazing thing, but it does have some uses…

I think Google Analytics UserID Views and Visitor Back Stitching is a good article that puts the utility of this View in perspective – it is worth a read.

…in a nutshell a configured User ID View

  1. Replaces Client ID with an actual User ID value when users are logged in.
  2. Allows you to view User activity across multiple devices. 
  3. Makes the User metric more meaningful.
  4. Allows you to access a few reports that are not normally available in Google Analytics – including Device Overlap and Device Acquisition.

n.b. the User ID View only includes a subset of your overall traffic. That subset consists of visitors that were assigned a User ID during their Session.

Ok… so hopefully all that makes sense and you can see how these different elements of Google Analytics measurement framework interact with each other.


User ID as a Customer Dimension in Google Analytics

Now, we get to the interesting one – sending the User ID/Customer ID as a Custom Dimension to GA.

Custom Dimensions are the dark horse of GA. Here is the background information.

I am not going to go through the explanation of Custom Dimensions and Metrics, I think that article does it well.

The short version is that they provide a way to get custom data into GA unified with the session data.

With the User ID/Customer ID as a Custom Dimension to Google Analytics – all Sessions, activity and ecommerce data is tied to a particular User.. IF the User ID/Customer ID is available…. similar to the User ID View.

So now we have this Custom Dimension available in all reports and a dimension/data set that can be exported into DataStudio (or whatever BI tool you are using), for further analysis and manipulation.

The point is, your shop CMS/sales management software has the data needed to calculate the customer retention rate – out of the box Google Analytics does not.

However, by sending that data via Custom Dimensions and Metrics you can combine it with session, engagement and acquisition data and it becomes powerful marketing intel.


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