Responsive Search Ads are the only ad format available in Google Search campaigns as of 2022. Expanded Text Ads were sunset — if you’re running search campaigns, you’re running RSAs. Google uses machine learning to test combinations of the 15 headlines and 4 descriptions you provide, then serves the combinations it predicts will perform best for each individual search.
The pitch is efficiency: instead of manually testing three or four text ads, Google tests hundreds of combinations automatically. The reality is more complicated. RSAs give Google significantly more control over which message each user sees — and without careful asset writing and deliberate pinning strategy, your ads can assemble into combinations that are incoherent, off-brand, or technically wrong.
How RSA Combination Testing Works
Google displays 2–3 headlines and 1–2 descriptions per ad impression. With 15 headlines and 4 descriptions, the number of possible combinations exceeds 40,000. Google’s algorithm learns which combinations generate higher CTR and conversion rates for specific queries, devices, user profiles, and times of day.
Over time, Google assigns each asset a performance rating: Learning, Low, Good, or Best. Assets rated “Best” appear more frequently. Assets rated “Low” may rarely show, even if they’re strategically important to you.
This creates tension: Google optimizes for CTR and conversions. You also care about brand accuracy, legal compliance, competitive positioning, and message consistency. The algorithm doesn’t know your policy constraints, your unique differentiators, or the specific positioning you’ve tested offline.
Writing Headlines That Work in Any Combination
The core challenge: any of your 15 headlines can appear alongside any other headline. Headlines must make sense independently and in combination.
Write standalone headlines. Each headline (30 characters max) should communicate a complete idea without requiring context from the other headlines shown. “Fixed Monthly Pricing” works alone. “That Fits Your Budget” requires a preceding headline and will fail when shown without it.
Avoid sequential dependencies. Don’t write Headline 1 as “Google Ads Management” and Headline 2 as “That Grows Your Business.” Google may show them together — or not. When shown apart, “That Grows Your Business” is incomplete and confused.
Cover distinct message categories. Structure your 15 headlines to cover different persuasion angles:
- Keywords/services (3–4 headlines): Include your primary keyword variations
- Value propositions (3–4 headlines): Price, speed, expertise, results
- Differentiators (2–3 headlines): What makes you different from competitors
- Social proof (2–3 headlines): Reviews, years in business, projects completed
- Calls to action (2–3 headlines): “Get a Free Audit,” “Start Today,” “Request a Quote”
Having variety in message category means whatever combination Google assembles, at least two of the three headlines serve distinct persuasive functions.
Use the character limit. 30 characters is not a lot. Use it. “Fixed-Price Google Ads — $697/mo” is more specific and compelling than “Affordable Google Ads Management.” Specificity increases CTR.
Include your primary keyword in at least two headlines. Google’s ad relevance scoring rewards keyword presence. The algorithm is also more likely to show keyword-containing headlines for searches that include that keyword. Two or three keyword variations (not identical) increase the chances a relevant headline appears for relevant queries.
Writing Descriptions That Stand Alone
Descriptions (90 characters each) have fewer combination issues because Google shows 1–2 descriptions per impression. Still, write each description as a complete message.
Each description should contain:
- A specific claim or benefit
- Evidence or mechanism
- A call to action or next step
Example: “Google Ads built with fixed pricing, full conversion tracking, and monthly reporting. Start with a free account audit.”
That’s 144 characters — too long. Revised: “Fixed pricing, full conversion tracking, monthly reporting. Free account audit to start.” (89 characters — within limit.)
Avoid descriptions that only add fluff (“We are committed to your success and look forward to working with you”). These aren’t just unhelpful — they take up a description slot that could contain an actual differentiator.
The Pinning Strategy: When to Use It
Pinning forces a specific headline or description to always appear in a specific position. Position 1 is the most prominent headline (left-most or primary). Position 2 is the secondary headline. Position 3 appears occasionally.
When to pin:
- Brand accuracy requirements: If you have a headline that must always appear (trademarked claim, legally required disclaimer, critical brand element), pin it.
- Keyword in headline 1: Many advertisers pin their primary keyword to headline 1 to ensure it always leads the ad.
- Call to action consistency: If your marketing strategy requires a specific CTA in every ad impression, pin it to headline 3.
When pinning hurts you:
- Pinning too many headlines: If you pin headlines to positions 1, 2, and 3, Google only shows those three headlines — you’ve effectively created a standard text ad and negated RSA’s combination testing.
- Pinning low-performing assets: Pinned assets don’t receive low/good/best ratings and don’t benefit from Google’s optimization. You’re forcing a combination the algorithm hasn’t validated.
The pinning approach that preserves RSA benefits: Pin one headline (your primary keyword or most important brand claim) to position 1. Leave positions 2 and 3 unpinned. This ensures the most important element is always present while letting Google test the remaining combination space.
To pin in the interface: When adding a headline, click the pin icon that appears on hover and select the position. You can pin multiple headlines to the same position — Google then selects from those pinned options rather than being forced to always show one specific headline. Pinning three keyword variants to position 1 and letting Google test which performs best is better than pinning one specific headline.
Reading the Ad Strength Score
Google provides an “Ad Strength” indicator: Poor, Average, Good, or Excellent. This measures how many assets you’ve added, how distinct they are, and whether they follow Google’s recommendations.
Ad Strength is not a performance predictor. It’s a compliance checklist. An ad with “Excellent” strength can underperform an ad with “Good” strength if the “Good” ad has more specific, compelling copy.
Add enough assets to reach “Good” strength. Don’t optimize the copy toward a “checker” at the expense of persuasion quality. The ad strength score rewards quantity and variety — it doesn’t evaluate whether any individual headline is actually compelling.
The Asset Performance Report
After 30+ days of traffic, check the asset performance report: Ads → Responsive Search Ads → Asset Details
Each headline and description receives a performance label. The metrics to act on:
- “Best” assets: These are working. Understand what they have in common — specific numbers, keyword presence, unique offer. Write more headlines with similar characteristics.
- “Low” assets: These appear rarely. They’re either redundant with better-performing headlines, too generic, or simply not resonating with your audience. Replace them.
- Assets still in “Learning”: Normal for newer campaigns or assets with limited impressions. Give them 30–60 days before evaluating.
Replace “Low”-rated assets with new copy. The asset performance report is your primary creative testing feedback loop — use it on a monthly basis.
Common RSA Mistakes
Adding 15 headlines and assuming the work is done. RSAs require ongoing asset performance review and replacement of low-performing assets. They’re not set-and-forget.
Using duplicate or near-duplicate headlines. Having three variations of “Expert Google Ads Management,” “Professional Google Ads Services,” and “Google Ads Experts” wastes three slots. Google needs variety to test effectively. If your 15 headlines are essentially the same message rephrased, you’re not giving the algorithm useful variation to work with.
No pinning on legally sensitive copy. If you’re in healthcare, legal, or financial services and have required disclaimers or specific factual claims, those must be pinned. Google’s combination assembly won’t know that headline 7 always needs to appear with description 2.
Ignoring the combination preview. In the RSA builder, use the preview at the bottom of the editor to check how different headline combinations read. Spend 10 minutes checking the most likely combinations before publishing.
Treating ad strength as ad quality. “Excellent” ad strength and excellent ad performance are not the same thing. Copy that scores “Excellent” on Google’s checker may still underperform because it’s generic, lacks proof points, or doesn’t speak to the specific search intent.
FAQ
How many RSAs should I have per ad group? Google recommends 1–3 RSAs per ad group. For most small business accounts, 2 RSAs per ad group is the practical optimum: one that follows your core messaging framework and one with alternative positioning to test a different angle.
Can I still use Expanded Text Ads (ETAs)? No. Google sunset ETA creation in June 2022. Existing ETAs continued to serve until they were paused or removed, but you can no longer create new ones. RSAs are the only format for Google Search.
What’s the difference between ad strength and Quality Score? Ad strength measures the quality and variety of your RSA assets. Quality Score measures expected CTR, ad relevance, and landing page experience at the keyword level. They’re related but separate — a high ad strength doesn’t guarantee high Quality Score.
How long before RSA combination testing produces reliable results? Typically 30–60 days for accounts with sufficient traffic. In lower-volume accounts (under 500 impressions/month for an ad group), the learning period is longer. Don’t evaluate asset performance with fewer than 30 days of data.
Does pinning reduce RSA performance? It can. Pinning restricts the number of combinations Google can test. Google’s own data suggests pinned RSAs see lower Ad Strength scores and often lower performance than fully open RSAs — but that tradeoff may be worth it for brand accuracy or compliance requirements.
Can I test two different value propositions in the same RSA? Somewhat. You can include headlines for two different value propositions (e.g., “Fixed Pricing” and “Flexible Monthly Billing”) and Google will test both. But if they’re contradictory, they may appear together, which creates a confusing message. Better approach: put contradictory messages in separate RSAs within the same ad group.
RSAs are the format you’re required to use — which makes understanding how to use them correctly non-optional. Our Google Ads management includes RSA copywriting, asset performance review, and ongoing replacement of underperforming headlines as part of every engagement. Get started, or run your current ads through honest.designodin.com to see how your asset mix stacks up.