Google Analytics – Sessions & Hits – Metrics Simplified Series

I’ll explain some of the key things about ‘Session’ metrics & hope to answer some questions like:

  • What is a google analytics session?
  • What is interaction and non-interaction hit?
  • Why are my %new sessions are higher than 100%?
  • How can I start and end the session manually? & more

 

Sessions: A session is a group of interactions that take place on your website within a given time frame

 

Let us understand what is an Interaction?

For that, you should first know what is a hit.
The hit is any interaction that sends data to analytics. A hit can be a:

  • Pageview hit (when user loads a page)
  • Event Hit (Needs Configuration)
  • Ecommerce Transaction hit (Needs Configuration)
  • Social Interaction hit (Needs Configuration), etc

 

Each of these hits can be further divided into:

  • Interaction Hit
  • Non – Interaction Hit

 

Interaction vs Non-Interaction Hit:

Sessions is only counted for interaction hits. Also the metrics like Bounce Rate, Avg. Session duration,etc depend a lot on the type of hit (Interaction and non-interaction). If the hit is non-interaction hit, they are excluded from the calculation.
By default, all hits are interaction hits. You can add:

before sending page view or event hit to make it a non-interaction hit

Experiment:

I have fired 2 non-interaction pageview hits and 3 interaction pageview hits. (both being different users)
Then, I have created 2 segments for these 2 users & 1 segment combining both the users naming Interaction + Non Interaction hits.
Lets see what we got:

So, the interaction hits resulted in 1 session while the non-interaction hits resulted in 0 sessions.
Notice how the metrics in the combined (Interaction & Non – Interaction) segment are reported. That would actually be the overall All users data you see everyday.

  • Users get counted in Non-interaction Hit but Session doesn’t.
  • Avg. Session Duration, Pages / Sessions, Bounce Rate ignore the non-interaction hits. But due to page views being counted in the non-interaction hit, the overall pages/session metric is actually Pageviews (All Hits) / Sessions (Interaction Hits).
  • %New Users is actually New Users (All Hits) / Sessions (Interaction Hits), so remember if you have encounter such a situation where it is greater than 100%.

 

Google Analytics Hierarchy – Users, Sessions & Hits:

Now lets understand the hierarchy of Users, Sessions & Hits as in Google Analytics.

Google Analytics Heirarchy - Users, Sessions & Hits

 

The session level comes in between the user and hit level. To understand Users more clear, you can check Google Analytics – Users – Metric Simplified, where I have explained about ‘user’ metric and how they are calculated in analytics.

 

Experiment:

Let’s understand the hierarchy through a live example, I have created the segment of my clientId naming Ritwik’s browser.

Date Range is Jan – 17:

As you can see, I visited the site for the first time on 9th Jan,2017 and had a total 11 sessions. Lets understand some key points here:

  • The User level is at the top in the hierarchy. So you can see that there is only one user here (i.e my browser).
  • A Unique user can have ‘one or more’ sessions. As you can see my browser had 3 sessions on 9th, 3 on 10th, 1 on 11th,…… and so on. This is the session level.
  • A Unique session can have ‘one or more’ pageviews. This is the hit level.

Here the user level is actually the browser level. If you change you device or browser or clear cookies,etc you will be treated as a new user. You can set up a user id tracking feature in analytics (more on this later) and that dimension will be at the top of the hierarchy given above.

 

You can also check Google Analytics – Users – Metrics Simplified to understand more about the users metric and why it is not additive (after applying secondary dimension) but the sessions and pageview metrics are.

Session Control: Starting/Stopping The Sessions:

You are free to decide when you want to start a session and end it. Let’s say, you have a blog within your website. Whenever someone enters your blog site (blog.example.com) you can start the new session.
So, you can also control the Avg. session duration metric by starting and stopping the sessions at particular hits. You can use ‘start’ and ‘end’ values for session control in a hit. The pageview hit code for starting the session is as follows:

 

Experiment:

Lets take an example.

I viewed 4 pages in a sequence :

  1. /sessions-start.html
  2. /session-start2.html
  3. /session-start3.html
  4. /session-start4.html

On the last second page, (/session-start3.html) I fired new session through the pageview hit.


Observations:

  • As you can see, new session started on /session-start3.html page, as it became the new landing page. Also, metrics which depend on the sessions like Avg. Session duration, Pages/Session, Bounce Rate,etc are calculated differently for both the session.
  • As session control code fires at a collection phase, you cannot experiment it on a test view separately. But you can do so in test property.

You can always experiment and come up with new use cases for your website.

Cheers.!!

 

 

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Ritwik is a Web Analyst & Product Marketer. He loves to write technical & easy to understand blogs for Marketers & Entrepreneurs. Focused on Google Analytics, Facebook Analytics, Tag Management, Marketing & Automation Scripts & more. Google Certified Professional. A Firm Believer in Teaching -> Learning -> Growing. :)

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