What are Dimensions and Metrics in Google Analytics?
In Google Analytics there are 2 types of data, Dimensions and Metrics. You will see them reported in a table, with the first column containing a list of the values for one particular dimension and the rest of the columns displaying the corresponding metrics.
Dimensions are the characteristics of your users and their sessions. A few common dimensions are the geographic location, the traffic source that brought the user to the site and an action a user takes on your site as in the name of the page they viewed.
Dimensions appear on all of your reports, though you might see different ones depending on the specific report. Use them to help organize, segment, and analyze your data. In some reports, you can add or remove some of them to see different aspects of your data.
Metrics count how often things happen – like the total number of Users/visitors on a website or app, they can be sums, ratio’s or averages – like the number of pages users visit during a session.
Under the metric “Users” you can measure the number of unique users that visit your site during a certain time period and also segment users into “new users” and “returning users”.
Sessions are a period of consecutive activity by the same user. By default a session is recorded until a user stops interacting with the site for 30 minutes. It is commonly known as a session time out. You can define the length of a session in your configuration settings. This is helpful if you have a video you want your user to watch, that is longer then 30 minutes.
It is important to understand that all of the time-based metrics rely on users activity, or hits to be calculated properly.
For example, to calculate the Metric “visit duration” Google anayltics subtracts the time of the user’s first interaction on your site from the time of the last interaction Remember an interaction could be viewing a page or watching a video. To calculate the metric “time on page” Google Analytics takes the time that a user landed on a particular page, and subtracts that from the time of the next pageview.
A very important metric to understand is “Bounce Rate” – it is the percentage of sessions with only one user interaction. Bounces are counted for users who land on a page of your site and leave immediately, without viewing any other content. Since these visits consist of only one interaction, Google Analytics does not have a second interaction to use for the calculation of visit duration or time on page, these visits are assigned a duration of zero.
The Relationship between dimensions and metrics
Although dimensions and metrics can stand alone, they usually are used in conjunction with one another. The values of dimensions and metrics and the relationships between those values is what creates meaning in your data. For the greatest insights, dimensions are often associated with one or more metric.