How to A/B Test Ad Call-To-Actions

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As advertisers, we are continuously trying to strengthen and optimize not only our strategy, but the effectiveness of our creative units.  A/B testing allows us to examine single variables and compare their performance directly against each other, allowing the tester to tweak and optimize for the best marketing return.  

Google was at the forefront of adopting this process, which started about 12 years ago and used it to determine how many search results they should lay out on one page.  To give you an idea of how much they utilize A/B testing, in 2011, they ran over 7,000 tests.

The beauty of A/B testing is we can use it for almost anything.  Take, for example, call-to-actions (CTAs), which are a critical component of any banner ad.  Hubspot found that text CTAs that were A/B tested increased conversion rates by 121%!  Not only that, but you can expect higher click-through-rates (CTR) as well when you optimize CTAs.  They are a hugely important factor in gaining clicks and tie directly into brand awareness brought on by your online ad campaigns.   

To give you specific insight, we’ve put together a how to A/b test ad call-to-actions below!  


If your focus is on your CTA, start as simple as possible.  Begin with the color scheme.  Test a palette of colors or single text color and then a completely different color set on your next batch of ads.  Launch each campaign at the same time, with the same number of ad units, in the same sizes, with the exact same targeting and flight dates. By keeping all variables except one equal you will be able to isolate what is really driving performance. As a general practice, don’t try and test multiple variables at the same time as it will be challenging to determine which variable was the actual driver of change.


It’s important to define your key performance indicators (KPI) prior to your test.  It’s best to have one main KPI that you are looking to improve then working towards it with methodical testing. In the example of your CTA, your main KPI should be Click-Through-Rate (CTR).  Run your test with the goal of improving this one metric. Test different text colors or Call-to-Action language (eg “Shop Now” vs “Shop the Sale”) to see what moves the needle most.


Once you complete your first A/B test you’ll have a baseline for how the two variables performed. For example, if you ran a test with blue text and red text and found that blue created the highest CTR, blue is the clear winner.  Perhaps on the next test you can try sky blue vs cobalt blue. From here, you can drill down even further. Use that winning color scheme and perform an A/B test changing the CTA language or perhaps font style.  


There are countless permutations you can choose from and plenty of things to A/B test, so be careful not to get carried away.  Once you’ve found something that works and drives the performance you desire, stick with that method for the time being and work on managing your new traffic.  After you’ve developed strategies around managing the influx in traffic, work on scaling up again using A/B testing as a tool.


In advertising, it’s easy to see how this trend started with the digital age and how it will keep expanding.  Now that ad space is cheap, and emails are free, what was once unfeasible financially for smaller companies is now attainable.

By using the outlined guide on how to A/B test ad call-to-actions, you’ll be in a much better position to make strategic marketing choices moving forward.

Any other tips?  Feel free to comment below!