A/B Test with Prefixbox – Prefixbox Documentation

A/B Test with Prefixbox


Measuring the Revenue / Conversion gains caused by Prefixbox.


Setting up an AB test where 50% of the users see Prefixbox, 50% of the users don’t see Prefixbox suggestions. The test should be run for 7 or 14 days.


1) Prefixbox Team

Setup an AB test on the Prefixbox Portal.

2) Customer

Setup GA tracking of the AB test as described below.

3) Prefixbox Team

Start the AB test and monitor results.

Google Analytics Configuration

Step 1

Prefixbox uses a user based, 1st party cookie (_prefixboxVariant) which contains the value indicating whether the user is on A (‘control’) or B (‘treatment’) version of the experiment. This cookie is “sticky” which means that a particular user sees the same version during the whole period of the test.

Step 2

Using GTM it is possible to read this cookie value, by using a “1st Party Cookie” User Defined Variable. Follow the steps on this picture to create the variable:

Step 3

When this is ready we need to configure/assign this GTM variant to the GA page view tag, as a Custom Dimension:

Step 4

It is important to note that the number “7” is probably going to be different in your case. Please check on the following GA Administration section the value of the Index, which Google Analytics has assigned to this dimension.

Step 5

After this we will be able to compare the analytics for the users on “control” and “treatment” during the AB test.