How To Optimize Google Responsive Search Ads (RSAs)

Now that RSAs (Responsive Search Ads) have replaced ETA (Expanded Text Ads) in Google Ads, it might be time to rethink your ad optimization strategies.

RSA optimization takes a very different approach than most advertisers have been doing for years.

While you’ll still want to use similar methodology to select variations of text to test, the way you go about conducting a test that yields statistically significant results has changed.

The RSA exam is different from the ETA exam

Ad testing used to consist of A/B experiments in which multiple ad formats competed with each other.

After collecting enough data for each of the competing ads, a winner can be chosen by analyzing the right metrics.

A common metric to determine a winning ad used a combination of conversion rate and CTR to calculate “conversions per impression” (conversion/puck).

The winning ad with the best price can be declared after sufficient data has been collected to allow for statistical significance.

This technique of searching for winning ads no longer works for three reasons.

Let’s take a look at what those are.

Reason 1: You can only test 3 RSAs per ad group

On ETA Ad Testing Days, advertisers can expand their A/B testing to A/B/C/D/… and keep adding more competitors to their experience until they reach a limit of 50 ads per ad group.

While I’ve never met an advertiser who ran 50 concurrent ads in a trial, I’ve seen many who test five or six at a time.

But Google is now capping ad groups with a maximum of three RSAs so that really changes the way things have to work in ad testing.

Reason 2: You don’t get full metrics for ad groups

Remember that each RSA can contain up to 15 headings and up to 4 descriptions, so one RSA can now be responsible for creating 43,680 differences.

That’s a lot more than the 50 different ETAs we’ve been allowed to test in the past.

Therefore, when a user sees an RSA, only a subset of the titles and descriptions that the advertiser submits actually appear in the ad.

Furthermore, what specific titles and descriptions are displayed changes from auction to auction.

When you compare the performance of two RSAs against each other, you are really comparing the performance of 43,680 possibilities for Ad A to 43,680 possibilities for Ad B.

This means that even if you find ad A to be a winner, there are too many uncontrolled variables in your experiment that invalidate any results you might find.

The Ad Groups reports in Google Ads show which RSA asset groups are shown as ads. Shot by author, 2022.

For more useful data, you should take a look at the Copy report which shows exactly which titles and descriptions were combined for each ad.

But the problem with this data is that Google only shares the number of impressions.

And to calculate a winning ad, we need to know CTR and conversion rate, both of which are metrics we no longer get from Google at this level of granularity.

Reason 3: Ad group impressions are now as much dependent on advertising as keywords

But perhaps the most surprising element of why ad testing methodology needed to be developed is that the old methods were created in a world that assumed impressions were based solely on ad group keywords.

RSAs have challenged this assumption and now ad group impressions can depend as much on ads as on keywords.

In Optmyzr’s May 2022 study of RSAs, we found that ad groups with RSAs got 2.1 times as many impressions as those with only ETAs.

Optmyzr RSA considers impressions for each ad groupPhoto courtesy of Optimyzr, June 2022

Regardless of whether this exponential increase in impressions for ad groups with RSAs is due to improved ad rank and quality score, or whether it is because Google has embedded a preference for this type of ad, the end result is the same.

The sandbox in which we play favors RSAs, especially those with the largest number of assets and which use pinning as sparingly as possible.

So when we do a recent ad optimization, we should consider not only conversions per impression, but also the number of impressions each ad can achieve.

Modern advertising test vs old school advertising testModern ad testing needs to consider differences in impressions.

A/B testing assets with ad variants

Fortunately, Google looked into the issues RSA introduced to test the ads and made updates to them Ad formatswhich is a subset of the ad optimization experience tools.

Instead of requiring multiple RSAs to be created, experiments run on assets and allow advertisers to test three types of things: install assets, swap assets, and add assets.

You will find all options in the left side menu for experiments.

Google ads listFind the different ad formats in the list of experiments in Google Ads.

Installation test

Pinning is a way to tell Google which pieces of text should always be shown in certain parts of an ad.

The simplest form of pinning tells Google to show a specific piece of content on a specific site. A common usage is to always display the brand in Heading 1.

Various options for installing adsImage courtesy of Google Ads, June 2022

A more advanced implementation is to pin multiple pieces of text to a specified location.

Of course, an ad can only display one of the pinned texts at any one time, so it’s a way to balance advertiser control with the benefits of dynamically generated ads.

A common use would be to test three variations of the brand message by anchoring all three variations to the Heading 1 position.

The most extreme form of pinning is to create what some call a “fake access ET” by pinning text to every position in RSA. Google recommends that you do not do this as it defeats the purpose of RSAs.

In our RSA study of Optmyzr, we also found that this type of pinning can significantly reduce the number of impressions an ad group can get.

But somewhat to our surprise we also found that fake ETAs have higher CTRs and conversion rates than pure RSAs.

One theory is that advertisers who have spent years perfecting their ads with ETA optimization techniques already have such great ads that machine learning may not offer much in terms of upside.

Effect of fixation on the performance of RSAsPhoto courtesy of Optimyzr, June 2022

To start an ad test with installation, look for the Ad Variation for option update text Then choose the desired action pin.

Google Ads user interface to pin ads to the experimentImage courtesy of Google Ads, June 2022

You can then create rules for titles and descriptions that need to be pinned to a variety of sites.

For example, you could say that any header containing your brand name should be anchored to the header 1 position.

One limitation is that you cannot create a variant experiment that will test install for multiple sites at the same time.

Asset addition test

Another experiment available with ad variations is to test what happens if certain assets are added or removed.

This type of test is well suited for testing larger changes, for example, to see what would happen if you included a special offer, a different unique value proposition, or a different call to action.

Google user interface for an experiment in RSAs where text is addedImage courtesy of Google Ads, June 2022

You can also use this to test an effect Ad personalization tools on your performance.

Some of the ad customizers available in RSAs are location insertion, countdown timers, and business data.

Asset replacement testing

The third and final type of sponsored ad testing in ad variations is testing what would happen if an asset were changed.

This type of experiment lends itself to testing more subtle changes.

For example, what is the effect of saying “10% off” instead of “Save 10% today”.

Both are the same symptom but expressed differently.

Google UI for ad variations to replace the original textImage courtesy of Google Ads, June 2022


Ad variant experiments automatically come up with the appropriate measurement.

For example, here you see the results of the test we did with the installation.

Statistically significant results are marked with an asterisk.

The Google Ads user interface displays the results of the ad variation testImage courtesy of Google Ads, June 2022

When you hover over the statistics, more details are revealed that explain the confidence levels of the trials.

The Google Ads user interface displays details of the result of the ad variant trialImage courtesy of Google Ads, June 2022

From there, it’s just a click away to promote winning quizzes to become part of your RSAs.

Something to note is that these ad variant tests are intended to be run at the campaign level or higher (co-campaign).

At this time, it is not possible to run an ad test for a single RSA or in a single ad group. Google said it is aware of this limitation and is working on a solution.


As Google’s ad formats change, it’s also time to change the way we test ads.

Ad variations are an easy way built into Google Ads to create experiences that work with assets rather than entire ads, and you can even test install.

Optmyzr’s latest RSA study showed that impressions now depend as much on having good ads as they do on having good keywords so working on ads that have the right mix of not only CTR and conversion rate but a lot of high impressions Quality is the modern way to improve PPC ads.

More resources:

  • How to Find and Improve the Best Player in the Game (Most Valuable Pages)
  • Avoid these top six mistakes in your remarketing campaigns
  • PPC 101: A Complete Guide to the Fundamentals of Pay-Per-Click Marketing

Featured image: Imagentle/Shutterstock

Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button