This document discusses how to set up A/B tests using Google Tag Manager. It explains two ground rules for A/B testing: 1) visitors are randomly assigned to variations, and 2) visitors stay in the same condition. Commercial tools like Optimizely and VWO are mentioned as doing fancy GUIs and ugly code well. The document then discusses replicating A/B test logic in GTM by assigning visitors randomly to conditions A or B, storing this in a cookie, and loading the proper code variation. It provides details on configuring the test, assigning visitors, using cookies, and triggering events and analytics. The goal is to allow setting up A/B tests for free using GTM's functionality.

1. SET UP (AND
ANALYZE) YOUR
A/B TESTS LIKE A
BOSS
USING THE GOOGLE TAG MANAGER
JULES STUIFBERGEN – CONVERSION HOTEL 2014

2. TOPICS FOR THIS
SESSION
• Two ground rules
• The added value of commercial tools
• What type of A/B tests am I talking about
• Can we replicate this functionality (using GTM)
• For free
• For kicks
• Because we can!
• Let’s find out!

3. A/B TESTING RULE 1:
RANDOMNESS
Visitors enter your experimentation zone
They’re assigned to a
variation (A or B)
randomly.
Then, they’re part of your
experiment.

4. A/B TESTING RULE 2:
CONDITIONS STAY THE SAME
Visitors are in the same condition, always.
Condition A
Condition B

5. THE ADDED VALUE OF
COMMERCIAL TOOLS
Optimizely VWO

6. THESE TOOLS DO 2
THINGS REALLY WELL
UGLY code Fancy GUI

7. WHAT TYPE OF TESTS
AM I TALKING ABOUT
• Same URL / page group
• Content manipulation with Javascript / jQuery
Meet jQuery. A big fat
Javascript library

8. LET’S REPLICATE THE
LOGIC
Pseudo code for a visitor entering the experiment
1. Does the visitor have a valid cookie?
1. Yes: set the condition variable w/ cookie value
2. No: Roll a dice and assign condition A or B
2. Store the condition in the cookie
3. Load the code for A or B
1. Javascript / jQuery code
2. Google Analytics code

9. READY TO CODE
YOUR TAG?

10. DETAILS: CONFIG
This code allows
endless amount of
variations.
One cookie per test

11. DETAILS:
ASSIGNMENT
In words:
If the cookie value is not in the
list of the variation names:
Pick a random variation.

12. DETAILS: COOKIE
Set the cookie, always.
This makes sure the cookie is renewed for 90 days
(code stolen from the interweb)

13. DETAILS: THE FUN
STUFF
This is where the
GTM magic begins.
abtest macros for
category, action and
label (from datalayer)

14. DETAILS: THE FUN
STUFF
This is where the
GTM magic begins.
Built-in event macro,
to trigger the action

15. RULE NR. 1
Fires on all abtest
events

16. MEASURE LIKE A
BOSS

17. RULE NR. 2 (AND 3..)
Fires variation
code

18. CODE LIKE A BOSS

19. OR.. CHEAT LIKE A
BOSS
Steal (and clean)
optimizely’s code using
the “edit code”
functionality

20. START YOUR
EXPERIMENT
This goes in a Tag
Activated by a
Rule

23. DEBUG YOUR
CONTAINER VERSION
LIKE A BOSS

24. WELCOME VISITORS..
http://datadatadata.nl/ch2014.html

25. AND ANALYZE THE
RESULTS
Use Google Analytics User
Segments on Events

26. YOU WIN!

27. THANK YOU
Jules Stuifbergen
@zjuul