A Guide to Testing PPC Ad Copy

Ad copy testing for PPC is a vital task. Not only does copy testing lead to very real and direct impacts on your click-through rates and conversion rates, but it also influences deeper perceptions of your brand. Adhering to our best practice guide will give you the greatest chance of making real improvements in your performance.

We’ll start this article by running through the key difficulties and misuse of ad copy. We’ll then move on to how to test it effectively and accrue real business benefits.

We’ve even produced a template to help you choose new ad copies to test in your campaigns. 

How to run ad copy tests on Responsive Search Ads

You can run A/B tests for pinning against not-pinning and compare the results.

As responsive search ads become the default PPC ad copy format, it’s important to continue running ad copy tests.

Whilst Google will optimise dynamically across the ad copies you have submitted, you can still raise the overall quality of those ad copies.

We’ve provided this and more information on how to improve the performance of your responsive search ads. We’ve also written here about how.

Mistakes to avoid when testing PPC ad copy

Ad copy testing is largely done very badly. Ad copy tests can even inspire fear among PPC specialists. 

This is because it’s often seen as a tedious task in this era of increasing click-and-go, dynamic optimisation search that we’re always moving into. This is particularly true with Google’s move to responsive search ads.

Make sure that you avoid these classic mistakes:

Don’t base PPC Ad Copy testing on CTR alone

If you’re only looking at click-through rates when testing ad copy, you’re doing it wrong. Anyone can serve an ad that will get people to click through more often, but does this really help your business objectives? If you’re serving ads that are fundamentally misleading—as in, they misrepresent your product or offering—you’re wasting money on worthless clicks.

Consider the advert below:

If I advertise that a product is “cheap” in my ads, then yes, it’s very likely to drive more clicks. However, my client is a family jeweller who values quality and local handmade products. Are people going to convert when they realise that my products are ten times more expensive than anyone else? Probably not.

If you’re a premium brand, let people know this before you’ve paid for their click. In the below advert, I’ve used language and price extensions to signal our higher quality and price range before we’ve paid for a click.

My click-through rate is likely to be lower here. But, I know that I’m driving higher quality, relevant traffic that’s much more likely to convert. You should measure ad performance based on a variety of factors, including Conversion Rate, ROAS, Pages/Session and Bounce Rate. These are all good metrics to look at alongside CTR.

This is particularly true of Responsive Search Ads, which Google have even suggested often lead to a lower CTR. However, they also often obtain a higher number of incremental clicks because the dynamic ad copy makes you more eligible for a large number of extra auctions. CTR isn’t king anymore.

Don’t make sweeping, account-wide conclusions

Often, you’ll look at how ad copy performs at an account or campaign level. Let’s take  a look at such an ad copy test, with three ad copy variants:

VariantClicksImpressionsCTRROAS
Variant 12,02444,9554.50%1.3
Variant 21,39437,1493.75%1.2
Variant 35,300122,3244.30%1.5

Variants 1 or  3 appear to be your best ad copy, right? Variant 2 certainly seems to be the worst performer in this view.

However, this analysis is made meaningless by the fact that it’s taking place across very different ad groups. All of your ad groups will have very different click-through and conversion rates. These have just as much of an impact on the result as the copy itself. So, we need to split them out.

To show this, let’s see the same (hypothetical) ad copies split into ad groups:

Ad GroupVariantClicksImpressionsCTRROAS


Ad Group 1
Variant 181014,0385.77%2.3
Variant 24187,6705.45%2.7
Variant 34,24082,8925.122.1


Ad Group 2
Variant 11,01230,9173.27%0.9
Variant 297629,4793.31%0.7
Variant 31,06039,4322.69%0.4

In reality, we see that Variant 3 is actually the worst-performing ad copy in both ad groups. It’s only among the top performers overall because it benefits from having the large majority of its clicks in the naturally stronger ad group. Either variant 1 or variant 2 - depending on your priorities-  now appear to be your strongest ad copies.

Our top 10 tips for PPC ad copy testing

1. Get your house in order first

Make sure you’re doing the PPC basics right first with your ad copy. Only then should you worry about the incrementals, like copy testing. For example:

  • Your headline 1s should be relevant to the specific keywords and work on quality score. 
  • Make sure there are three ads in each ad group. 
  • Have a relevant Path 1 and 2. 

Then, and only then, should you start worrying about testing.

2. Have an ad copy testing plan

Don’t just test for the sake of running a test. It wastes your time and your client’s money. Know what you’re going to test and know what KPIs you’re using to measure them. At Ayima, we build complete testing dashboards to help us and clients plan and conduct tests that will help not just PPC, but all marketing channels

3. Only test things that will likely have an impact

Again, there’s no point in testing minute changes to ad copy that no one will ever notice. Don’t test using the word “they” rather than the word “them”. The longer you spend testing ad copy, the more time your data is split, and the less traffic you’re sending to your best ad copy.

4. Incorporate human biases in your ad copy tests

Try testing ad copy hacks that use fundamental human biases. Examples of this might be:

  • Does placing more trust signals in ad copy work?
  • Test placing adjectives in headline 1, where people will actually read them.
  • Try implying something in your paths.
  • Use fewer characters. In a world of split-millisecond viewing, the whitespace around your ad could be more important than the words within them.

We have more tips and ideas in our template

5. PPC ad copy is different to other channels

Remember that PPC ad copy has slightly different principles to other channels- relevance to the search query is still absolutely vital. It’s different to sell to someone already demonstrating purchase intent, but you can still test broad principles.

6. Measure ad copy tests at an ad group level

We showed above the dangers of aggregating ad copy tests at an account level.

Always look at results at an ad group level, and look at all the right metrics. If you can, find or develop a tool to help you conduct tests, as we’ve built with Ayima Intelligence. If not, start looking more in-depth manually. If not, your insights could be miles from the real picture.

7. Embrace Responsive Search Ads

Responsive Search Ads are here to stay. Google’s algorithms are good for optimising at scale so that you don’t have to. But, you can and should still test on RSAs to improve the quality of your overall bank of ad copy. We’ve produced a comprehensive guide to responsive search ads.

8. Test your ad extensions

Google is constantly improving the Search Page experience. A major aspect of this is providing people additional information on the search page before they click through. Sitelinks and extensions allow them to customise each ad even more to the user and the search query.

Sitelinks are also far more noticeable than description two on a search page. With the exception of Headlines 1 and 2, this should probably be your next highest priority by value-added.

We’ve developed a tool that even crunches website data to select the best ad extensions for every campaign. The tool analyses user-flow at the campaign and ad group level and picks the top 5 pages to build sitelinks for. This even let us adjust sitelinks at scale to match user behaviour.

The impact was fantastic. In testing, we achieved a 17% increase in sitelink CTR on the test vs control group. We even increased conversion rates through sitelinks by 4% by making them better “shortcuts” to where our users needed to go.

9. Apply your ad copy learnings to PPC, and other channels

Actually apply your ad copy tests. Work with your clients or teams and test the more effective messaging in other channels. PPC copy tests have fantastically large sample sizes, so it’s about time we start to use them effectively.

In particular, you can use your PPC ad copy test results on your website to improve your SEO CTR curve

We’ve produced an in-depth guide to integrating your PPC and SEO if you want more on how to make the two work together.

10. Test for Statistical Significance

Some PPC Analysts don’t measure the statistical significance of their ad copy test  because it takes more time to do and often clouds results. Whilst there’s a clear winner in the top example, you frequently get a different winner for every ad group, with no recognisable patterns in the bottom example. Moreover, measurement is often unreliable because the winner keeps on changing.

There was a fantastic analysis at a PPC Hero talk in 2017 that tracked an ad copy test over time. It highlighted that one variant became a statistically significant winner for a few days before swinging back to dead even, to the other copy becoming visibly better before the whole process repeated itself. The results literally depended on when you measured it.

Always make sure to test the statistical significance of your ad copy tests.

How to run statistically significant PPC ad copy tests

There are a number of free tools online to test statistical significance. There are also several techniques they use to do so. We use our own tool that we built using Bayesian Statistics. 

You can see this tool below. 

Whilst Variant 2 appears to be slightly better, it only has a 60% chance of being the best ad copy. You can see within the bell curves on the right-hand side how the grey region slopes down well to the right-hand side, that Variation 1 might even be a whole lot better than Variation 2.

We recommend using Bayes to test ad copy for three main reasons:

  1. It is much easier to understand for non-statisticians - it provides a simple “probability of being best” for each variant
  2. Bayes is better than the standard approach (the “frequentist” approach, for the stats nerds) for testing more than two variants
  3. It also produces an “expected loss” metric. This tells you what percentage of traffic you can expect to lose if the “better” copy is actually worse. This all helps you to weigh up your options with the greatest information.

Your risk appetite may vary, but we recommend only selecting a winner if it gets at least a 90% chance of being the best ad copy when using this model. 

In Summary

There are fewer testing grounds more powerful than PPC for ad copy. With its millions of easily accessible and cheap impressions and clicks, plus the ability to monitor these very granularly, it’s a quick tool to effectively gather broad learnings on which indicators in your copy work for your brand.

However, there are several reasons why you might not be using this to its greatest possible effect and even more pitfalls to avoid when measuring it. By following our 10 top tips for success set out above, you’re well on your way to getting the most out of your PPC efforts.

Template for PPC Ad Copy Testing

We’ve created a template for members of Ayima Insights Club. This helps people to come up with ideas for PPC ad copy tests. You can then place these in a testing dashboard and keep track of what tests you’ve run, statistical significance, and current ad copy.

You can join Ayima Insights Club for free to get access to this template and many others like it.

Learn about our free, personalised insights club

More Insights

June 2022 Digital Roundup

30 June 2022

May 2022 Digital Roundup

06 June 2022

Tips to optimize your Google Product Feeds

06 June 2022