The quick answer is:
An additional report dimension for more specific analysis
What Does That Mean?
Google says:
“The Secondary Dimension feature allows you to define a primary dimension and then view that data by a secondary dimension within the same table.”
In other words, it’s a way to see more data about your website’s visitors.
Start At Primary Dimension
To find the secondary dimension options, you’ll first need to navigate to a primary dimension first.
That basically means one of the options you choose in the left sidebar menu.
For example, let’s say you want to check your organic traffic coming from Google searches.
On the left side, you would click Acquisition > Overview.
Then in the main window select Organic Search.

Towards the top right of the screen, you can adjust the timeframe for the data you want to check.

Finding the Secondary Dimension
In this example, your Primary Dimension is: Keyword
And you’ll see the option to click “Secondary dimension”.

When clicked, you’ll see options to explore that include:
- Acquisition
- Advertising
- Behavior
- Custom Variables
- Ecommerce
- Social
- Time
- Users

This Is How to Find Great and Specific Data about Your Website
Each of those options have many options within them. Click the option you are interested in and start exploring the data.
For example, if you select Users, then scroll down and select City.

That will add a column in your data table with info about the cities your visitors are in.

How Can That Be Useful?
If you are targeting local searches near you, then you would be able to see if your local SEO consultant’s campaign is working.
Doing your own SEO?
In the example above, let’s say you are targeting web visitors in or around Chicago, IL.
And you check your users’ city data using Google Analytics secondary dimensions and see most of your traffic is coming from other countries, then you might want to re-evaluate your SEO campaign and strategy to make sure you start getting the local traffic you want.
There Are Many Ways to Use Google Analytics’ Secondary Dimensions
There are tons of different ways to use the secondary dimension feature. Click around with the different choices available to uncover a lot of your website’s user data. It can get interesting, like our SEO outsource services!
Other Reading: How to Exclude Words From Google Search
Secondary dimensions are very helpful when analyzing data and traffic in Google analytics. It really helps break down website traffic.
Nice, and thank you for that quick answer to the question.