Metrics and dimensions are the building blocks of Google Analytics that help you segment, organize, and analyze your traffic data—so let's dive into the distinction between the two, and how they can be combined.
Google Analytics reports are made of dimensions and metrics. Throughout most reports, metrics are the quantitative measurements of data and dimensions are the labels used to describe them—or, in even easier terms: metrics are always expressed by numbers (number values, %, $, time), while dimensions are expressed by non-numerical values.
Now let’s drill down into each separately.
Dimensions are the attributes that can be used to describe and segment, organize, and sort the data by. Examples of dimensions include:
Each dimension accepts different values: for example, the dimension ‘Device Category’ indicates the type of device used to visit a website, accepts ‘desktop, mobile, and tablet’ as values, and can help sort traffic between the three devices.
Each GA report comes with a pre-selected primary dimension that gives high-level insight into how the dimension performs in relation to a set of metrics.
Across most reports, a full list of dimensions can be seen by clicking on ‘Other’ in the Primary Dimension menu and scrolling through the drop-down option. To change the primary dimension, users can pick the most relevant one from the list of all available options.
While primary dimensions appear by default, secondary dimensions can be added to further drill down into the data.
For example: using ‘Device Category’ as a primary dimension, your data can be sorted across the values of desktop, mobile, and tablet:
But applying ‘Browser’ as a secondary dimension from the ‘Secondary dimension’ drop-down menu means that now you can also review how different browsers perform on each device:
In addition to using default dimensions, GA users can create custom dimensions to collect and measure data the tool wouldn’t automatically track—for example, information stored in a Customer Relationship Management (CRM) system that can be synced with GA data. Custom dimensions are particularly relevant for ecommerce owners, who can review data points like the total value of unpurchased items in a cart or the difference in the behavior of logged-in vs. guest customers.
Things get quite technical at this point, and Google has an exhaustive list of prerequisites and configuration options to introduce custom dimensions into your account.
Metrics are expressed through numbers (number values, %, $, time) in a Google Analytics report: they are quantitative measurements of data and show how a website is performing in relation to a specific dimension.
For example, the number of ‘Users’ who came from desktop, mobile, and tablet devices and their ‘Average Session Duration’ are metrics for the Device Category dimension:
The most common metrics in GA—that is, the ones you see by default as you log into GA—are usually grouped into Acquisition, Behavior, and Conversions metrics:
We promised at the top of the page that we’d dig a bit deeper into why dimensions and metrics in GA paint an incomplete picture.
First of all: dimensions and metrics are incredibly useful to help you understand the performance of your site as a whole and any of its individual pages. They help you:
However: while GA helps you keep the ultimate log of everything that is happening on your website, it still can’t tell you exactly WHY your visitors behave in the way they do.
Practical example: you learn from looking at your GA metrics that one of your newest product pages has a 75% exit rate, meaning 7.5 out of 10 people who make it there leave the website:
You can dig into the data using different dimensions (e.g. Device Category, City, Traffic Source) and form a few plausible hypotheses, but you cannot really know for sure:
If you are looking to dig deeper into the drivers behind your customers’ behavior, the barriers they experience as they navigate across your site, and the hooks that ultimately get them to convert, you’ll want to combine the insights you get from GA with behavior analytics and feedback tools. They include:
Don’t stop at dimension and metrics: there’s a lot more to find out about your website visitors, and tools like heatmaps, session recordings, and on-site surveys help you dig deeper and get to know them better. When you combine the data pulled from GA with the insight collected from behavior analytics tools, you’ll start getting a complete picture of: