A dimension is a data attribute and has a non-quantitative value. A metric is paired with a dimension and has a quantitative value. For example, a page title is a dimension, and a page view is a metric.
When you look at any core report in Analytics, a dimension will appear in the first column. In other columns, usually will be metrics. Sometimes, the report will also have nested dimensions. For example, the page report has a dimension
page title, metrics
unique page views,
bounce rate, and
exit rate. It also has nested dimensions, such as,
Dimensions and metrics belong to an event or a session scope. An event is an individual interaction during a session. A session includes all events during an entire visit. We can illustrate the difference between them in the following way.
Now, let’s see a few examples.
Here are some samples of dimensions from an event scope:
- Page URL: The URL of the page on which the event was tracked.
- Search keyword: A query that a visitor typed in the search on your website.
- Goal name: The name of a goal set for your website.
Here are some samples of metrics from an event scope:
- Page view: The total number of times a page was visited.
- Searches: The total number of searches on your website.
- Goal conversions: The total number of conversions for goals.
Here are some samples of dimensions from a session scope:
- Campaign: A campaign from which a visitor came to the website and started a session.
- Device type: The type of the device used by a visitor during the session.
- Session entry URL: The URL of the page from which the session has started.
Here are some samples of metrics from a session scope:
- Sessions: The total number of sessions.
- Average session time: An average time of session duration.
- Bounce rate: The percentage of sessions during which visitors viewed only one page and didn’t continue to another page view, goal conversion, or e-commerce conversion.
Now, let’s take a closer look at how data is calculated for a report. This will help you better understand dimensions, metrics, and scopes.
Here’s an example of events that happened on the Clear Bank website.
|Event type||Page URL (path)||Device type||Goal name||Goal revenue|
|Event 1||Goal conversion||/product-tour/||Desktop||App signup||$50|
|Event 2||Site search||/help/||Mobile||–||–|
|Event 3||Page view||/blog/||Mobile||–||–|
|Event 4||Goal conversion||/blog/||Desktop||Newsletter signup||$5|
Everything that you can see in the header row of the example is a dimension — event type, page URL (path), device type, goal name, and goal revenue.
A metric is something that can be calculated for a dimension. Let’s see two examples.
|Page URL (path)||Events||Goal conversion||Sum of goal revenue|
In this case, a page URL (path) is a dimension, and events, a goal conversion, and a sum of goal revenue are metrics.
|Device type||Events||Goal conversion||Sum of goal revenue|
In this case, a device type is a dimension, and events, a goal conversion, and a sum of goal revenue are metrics.
Some metrics are simple counters, others are calculated based on dimension values. For the latter, you need to convert a dimension to a metric. Also, when you use a metric calculated from a session dimension, you can’t pair it with an event dimension. See this article to learn more about it.