A Glossary of Major Google Analytics Metrics and How they are Calculated!

Google Analytics is the popular free tool we use to keep an eye on the traffic flowing to our websites and the various activities happening on it. Ideally, this should help us understand our users and optimize our users experience and strategic goals accordingly .

But do we really understand how each metric works?

Do we know how to translate these metrics into actionable insights?

Below is a list of the most frequently used GA metrics and how each is calculated. In an upcoming article we’ll discuss how industry experts interpret these metrics.

Sessions, Visits and Users

session is by default a period of user activity not interrupted for at least 30 mins. Consequently a single user can increment the sessions count by two or more from a single visit. GA tracking code stores a ga_cookie in users browsers that would allow it to recognize a returning user. Yet, if the user decides to erase cookies or switch browsers, the same user will increment the user count by 2 or more. That’s why GA data is not always 100% accurate.

Note: Previously GA used to report visits and unique visits, now it only reports sessions and users most probably because the terminology is more accurate. Since effectively each physical visit can generate multiple sessions.

Pages/Session, Pageviews and Unique page views

Pages per session as a metric is relatively obvious, yet it gains its importance since it’s considered an engagement metric.

Pageviews metric reports the total number of times the GA tracking code is executed on a page including repeat views of a single page. It can be reported on a landing page level or globally as the sum of pageviews of all landing pages.

Unique Pageviews is a count of the sessions in which a landing page have been viewed at least once. Here repeat views do not count.

Average Session Duration and Average Time of Page

The way Average Session Duration is calculated, is very counter intuitive. If you think that the session duration is being recorded starting from the moment your session starts and ending with the moment your session ends, then you are wrong. GA Session duration is actually the amount of time between a session start and the moment you take an action (via a Click or event). i.e. If you visit only one page of the website and leave without clicking to another page, your session duration will be 0:00:00. That’s why one need to be careful when interpreting such metrics. This complication is due to the fact that GA has no means to calculate a session duration other than calculating the time difference between two interactions. If you initiated one session and left without engaging in some way, then GA will have no clue how much time you’ve spent.

Average Time on Page which is a metric used in site content reports is a bit different. It is calculated by dividing the total time spent on page by the number of instances (Events do not count here!). So, in most cases the number of instances is 1-which is a click to some other landing page. While many events can take place during a session, basically only a click to another page can press the ‘time on page’ stopwatch !

Bounce Rate and Exit Rate

Bounce rate is a page level metric. It indicates the percentage of single-hit sessions received by a landing page. You can think of a single-hit session as a session with session duration of 0:00:00-as calculated by GA.

The difference between Percent Exit and Bounce Rate is the difference between a bounce and an exit in GA’s perspective. A bounce is calculated whenever you leave the website, while an exit is calculated whenever a session ends. Effectively, the exit page is the last page that is accessed during a session. The number of exits that happen on landing page divided by the total sessions received by this landing page is what makes the percent exit metric.


Main Source: Google Anlytics Breakthough: From Zero to Business Impact

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