In our continuing series on RSAs, we will take an in-depth look at the RSA ad strength. In this post, we will cover:
- How many headlines you need to achieve an ad strength score of ‘Excellent’.
- How pinning affects your ad strength.
- How ad strength correlates with impressions, CTR and conversion rate.
What is Ad Strength?
Ad strength is a score Google gives your RSA based upon the total number of assets (headlines and descriptions) and the diversity of those assets within an RSA.
Google has four categories of ad strength:
- Poor
- Average
- Good
- Excellent
As you add or edit headlines, your ad strength changes dynamically. In addition, Google will show suggestions to improve your ad strength.
One of the suggestions often seen is not to pin the assets. This is a controversial action, so we’ll take a look at how pinning affects ad strength.
How the Comparisons were Conducted
We used data from several thousands of accounts to find RSAs that met the following conditions:
- We used RSAs that are currently active (in enabled campaigns/ad groups). The sample size is well over 1 million ads.
- Whenever we measured the impact an RSA attribute (e.g. ad strength) has on its performance, we compared the performance of only RSAs running within the same ad group. This ensured the RSAs being compared were subjected to the same targeting conditions and hence as many irrelevant factors were isolated as possible.
- Whenever RSAs were compared against each other, we used only ones that have all been running for at least 2 months while considering only the last 30 days of performance data. This minimizes the impact the initial learning phase of an RSA has on the data we use.
By following the above criteria in selecting the RSAs we are confident the conclusions reached in this post are as accurate as possible.
How Many Headlines You Need to Get an ‘Excellent’ Ad Strength
When we look at ads with Excellent ad strength, most of them have at least 13 headlines, although some had only 8 headlines. No RSAs with under 8 headlines had an Excellent ad strength.
When the above analysis is done for ‘Good’ ad strength, we found one needs a minimum of 4 headlines to achieve a Good ad strength.
Ad strength isn’t only about the number of headlines you have. Google also checks if your keywords are in the headlines and if you have diverse enough content in your headlines. To confirm that ad strength is not only dependent on the number of headlines but rather on the content as well, we examined RSAs that have Poor ad strength and found the majority of them have 15 headlines.
This confirms we cannot enhance the ad strength by simply adding more headlines. We still need headlines relevant to the ad group that are different from each other.
If you have more than 8 headlines and do not yet have an Excellent ad strength, look at Google’s recommendations for ad strength. If you see a recommendation to ‘add keywords to the headlines’, and your headlines already have some keywords in them, look at the keywords in your ad group and see if some of them need to be in a different ad group to have more relevant ads associated with those keywords. Our previous article looked at RSA creation and how you still need well-organized ad groups even with RSAs and their potential headline diversity.
How Pinning Affects Ad Strength
To examine the relationship between pinning and ad strength, we split our RSA data set into three categories:
- Unpinned ads: no headlines are pinned
- Partial pinning: 1 or 2 headlines are pinned
- Full pinning: All 3 headlines are pinned
We then counted the ads in the above categories segmented by ad strength.
From the above, we can see it’s extremely unlikely to have an Excellent ad strength with any degree of pinning. However, ads that use full pinning can easily achieve a Good ad strength. If pinning is part of your strategy, aim for a Good ad strength (since an Excellent score is much harder to achieve).
How Ad Strength Affects Your Impressions
If you have multiple RSAs in an ad group, do their ad strengths affect the impressions they get? To conduct an accurate comparison, we considered only ad groups where all RSAs used a very similar pinning pattern (to isolate any impact pinning might have on impressions).
When we examined this data, we see the RSA with the higher ad strength gets more impressions 56.8% of the time. However, the RSAs with the lower ad strength had more impressions 36.6% of the time. We conclude there doesn’t seem to be a clear or strong relationship between ad strength and impressions. Within an ad group, an RSA with higher ad strength will likely, but not always, receive more impressions than the RSA with the lower ad strength.
To further analyze the above, we also looked at how the impressions differed with the degree of difference in ad strength and found there wasn’t much of an impact. For instance, the way the impressions differed in an ad group with ad strength of Excellent vs Poor was very similar to when the ad strength was Excellent vs Good.
How Ad Strength Affects CTR and Conversion Rate
To examine any relationship between ad strength and CTR or Conversion rate, we again considered only ad groups where all RSAs used a very similar pinning pattern.
In the above chart, we can see that the higher ad strength ads had a lower CTR than the lower ad strength ads in 51.5% of the cases. This number is immaterial and ad strength and CTR do not seem to have any direct correlation.
For the conversion rate comparison above, we once again see that the higher ad strength ads had worse metrics than the lower ad strength ads in the same ad group.
In looking at these charts, there does not seem to be a direct relationship between CTR or Conversion rate and the ad strength. We looked at this data in a few different ways and reached the same conclusion in each scenario.
Given the above where no strong correlation was found between ad strength and the ad’s performance, it seems ad strength is purely a measure of Google’s ability to test the RSA, and that having a high versus a low CTR did not impact the ad strength.
How Pinning Affects your Ads Performance
In a lot of our analysis, we often found higher CTRs or conversion rates achieved by ads that use pinning. However, the act of pinning by itself does not have an impact on performance. If you are pinning well written assets then, just like writing any good ad, it is common to see higher CTRs and conversion rates due to the better ad seen by the searcher. On the other hand, pinning poorly written assets would typically result in worse performing ads.
The more unpinned headlines you have, the more variations of ad combinations Google’s machine learning needs to test and optimize. Pinning good headlines often shortcuts the learning process since you are giving the machine fewer variables to work with. Assuming you are only pinning well written headlines, you will almost always see an improvement in your ads performance.
Wrap-Up
This might seem controversial, but having an Excellent versus Poor ad strength does not seem to affect your account in any significant way. We conclude from our research that:
- Ad strength seems to be mainly a reflection of Google’s ability to test your ads and the diversity of those headlines.
- If you use at least 8 headlines, it is possible to get an Excellent ad strength. However, it is much easier to do so with 13 or more headlines.
- Your ads could all have a Poor ad strength but still maintain high conversion rates. You could improve your ad strength from Poor to Excellent and not see a significant improvement in CTR or conversion rates.
- If you have at least 2 RSAs in an ad group, the RSA with the higher ad strength will generally get more impressions, but there are many exceptions to this.
- While it might be possible to get an Excellent ad strength when you pin your headlines, it is rare. A Good ad strength is, however, easy to achieve with pinning.
As Google’s RSA machine learning improves over time, we may see changes to the above conclusions and other account factors. As always, however, the main goal should be to create RSAs that convert regardless of their ad strengths. As you plan the transition from ETAs to RSAs, feel free to check our best practices on how to Create and Test RSAs.
This RSA Optimization Series brings you all the knowledge you need to manage the ETA to RSA transition and achieve your account goals with RSAs.
