Custom Segmentation with Google Analytics

Last week wrote a piece about using custom segments to exclude yourself from Google Analytics tracking. I didn’t stop to think that some folks may not know what custom segmentation is and how it is implemented with Google Analytics. So today I’ll cover how to setup and use custom segmentation with Google Analytics.

Segmentation of data involves slicing the data based on some visitor characteristic. A very common data segment is new and returning visitors. This means that we can look at the website traffic and identify what portion is generated from new visitors, what portion is generated from returning visitors and what those groups did while on the site. Google Analytics has a number of pre-defined segments that you can find in the Marketing Optimization > Visitor Segment Performance reports.

In addition to these standard segments, you can define your own custom segment. This means you can divide your traffic into various groups, as defined by you, and then observe how those groups interact with your marketing activities and your website.

If you need more information about segmentation, or why you should do it, you can or you can read an article on ClickZ. There’s a bunch of them.

So, how do we add a visitor to a custom segment with Google Analytics? We use a JavaScript function to set a special cookie on their machine. The function is named __utmSetVar(’v’) and the cookie is named __utmv. We can call this function any where JavaScript can be called. When you use this function replace ‘v’ with some value. This is the value that will be stored in the cookie and will be visible in your reports. Here’s an example.

Let’s say we have a contact form on our site and we ask the visitor to specify their gender. There is a drop down box with the different responses. We can call the the __utmSetVar() function when the value in the drop down box changes. This will set the user-chosen value as a custom segment. After the segment has been set all of the visitor’s activites will be ‘bucketed’ into that segment.

There are a number of ways to view how your custom segments perform. The easiest way is using the Marketing Optimization > Visitor Segment Performace > User-Defined report. This shows the visits, average page views per visit, and goal conversion rate for your custom segments.

You can also cross segment many Google Analytics reports based on your custom segemtns. To do this click on the red chevron at the left side of a report (like the Top Content report). Then choose Cross Segment Performance and User Defined. GA will segment that line item based on your custom segments.

There is one major limitation to the Cross Segmentation functionality. You can only set one custom segment cookie at a time, therefore you can only set one custom segment, per visitor, at a time. Luckily this is pretty easy to get around. Recently, I wanted to track the conversion rate for certain genders and age groups. So I wrote some custom JavaScript that takes the gender data and age data from a form, combines it into a single string, and then sets the custom segment cookie. When the __utmSetVar() function is called it looks like this:

__utmSetVar('male:25-35')

‘male:25-35’ would be the value stored for a ‘male’ in the age group of ’25 to 35′. This value dynamically changes based on the data the user enters into the form.

That’s about it. Questions? Comments? Just want to say hi? Leave a comment below.