Segments are like subsets of the Google Analytics (GA) data and work like filters. This means that you can navigate around the various GA generating reports based on just that subset of data without having to apply a separate filters for each report.

There are many different types of segments you can create e.g. by users or the type of session behaviour etc. but the most common use case at Imperial is to have reports based on a certain page or section of the website, so these instructions are based on doing this.

If you want to learn more about the other types of Segments you can refer to the Google Anlaytics help site.

How to add a Segment

1. Go to the type of report you want e.g. New vs Returning

2. Click on + Add Segments

Click + Add Segment on the report screen3. Give your Segment a name (something meaningful to you)

Name the Segment and click Conditions4. Click Conditions
5. Click on the first drop down box (in this case Ad content) and type ‘Page’ in the search box. Scroll down the filtered list and click on Page.

Select Page from the filter list


6. Change the second drop down option from ‘contains’ to ‘starts with’ and enter the web address of the section you want to look at minus the e.g. /research-and-innovation/support-for-staff/stats-advice-service/

Enter your web address filter

7. Click Save. This will then apply the Segment (filter) to your Google Analytics session. 

Save and apply your filter

And you will see your filtered report.

Your filtered report

Data sampling

One thing you should be aware of when you add Segments or other filters (dimensions) is that it can affect the accuracy of the report.

The more you increase the date range or add further Segments and filters, the more likely your report will be based on a sample of data. To check this, you will see a small shield icon next to the report name.

Report accuracy icon


If this is green then this report will be based on 100% of sessions. If it is amber, then it will be a sample. To find out how big or small this sample is then hover your cursor over the icon. 

% of sessions the report is based on

What this means is that only a sample of 26.12% has been used, and it has been scaled up so in this case the sample data has been multiplied by ~3.83 to represent 100% of the sessions. You can only be confident that 26.12% of the data is accurate.


If your percentage is low i.e. less than 40% you should consider reducing the date range or complexity of the filters. There is more information on the Google Analytics help site.