Does Google's Ad Strength Score Predict Conversions? What 5,900 Accounts Show

No. According to Brad Geddes' study of more than 5,900 Google Ads accounts, the higher-rated ad had the better conversion rate in only 45% of ad groups, yet Google still showed it more often. Ad strength measures how varied your ad copy is. It doesn't measure whether the ad books jobs.

That finding comes from a write-up by Greg Jarboe at Search Engine Journal. Geddes is co-founder of Adalysis, and the study looks at responsive search ads (RSAs), the default Google Ads text format. If you run Google Ads for a plumbing, HVAC, roofing or electrical company, the numbers are worth ten minutes of your time.

What does Google say ad strength actually does?

Google says ad strength is a guide for writing your ads. It is not used to calculate Ad Rank, Quality Score or auction wins, and it doesn't directly decide whether your ad is eligible to show. Google's Ads Product Liaison, Ginny Marvin, repeated this in a March 2024 post on X.

I take Google at its word on the mechanics. The score isn't a bidding input.

But "not an auction input" and "doesn't affect which of your ads gets shown" are two different claims. As Jarboe points out, Geddes' data speaks to the second one. That's where it gets interesting for anyone running more than one ad in an ad group.

Does Google show higher ad strength ads more often?

In this data, yes. In ad groups with two active ads sharing the same keywords, bids and budget, the higher-rated ad got more impressions 63% of the time. An Excellent ad beat a Poor ad on impressions in 78% of ad groups. The pattern held even when ratings were close.

Here is how the gap changed with the distance between ratings, per the study:

Excellent versus Poor: the higher-rated ad got more impressions in 78% of ad groups.
Ratings two steps apart, such as Excellent versus Average: 66%.
The closest matchup, Good versus Average: 59%.

Geddes isolated ad groups with two ads because it strips out a lot of noise. Same keywords, same bids, same budget. When the inputs are that similar, the lean toward the higher score is hard to ignore.

This is observational data, and Google might dispute the word "reliance" for what Geddes sees. But if you're testing two ads against each other, you should assume the system won't split traffic evenly.

Do higher-rated ads actually convert better?

Not usually. The higher-rated ad had the higher click-through rate in 52.5% of ad groups, barely better than a coin flip. It had the higher conversion rate in only 45%. That means the lower-rated ad converted better in 55% of ad groups.

Cost tells the same story. According to the study, the lower-rated ad had the lower cost per acquisition (CPA) in 51.5% of ad groups. Across all ad groups, the higher-rated ads ran an 11.8% higher CPA. In the example Geddes uses, a lower-rated ad with a $100 CPA would face a higher-rated rival at $111.80.

On conversions per 1,000 impressions, a metric Adalysis calls CPI, the lower-rated ad won 54.3% of the time.

Think about what that means in a real account. Google sends more of your budget to the ad that looks better on paper. That ad is the slightly more expensive way to get a lead more than half the time.

Is Google leaning harder on ad strength than it used to?

Probably, according to the study. Adalysis ran a similar study in 2022, so Geddes can compare. The higher-rated ad won on impressions in 56.8% of ad groups in 2022 and 63% in the new study. It won on CTR 48.5% of the time in 2022 and 52.5% now.

Conversion rate didn't move with them. The higher-rated ad had the better conversion rate in 45.8% of ad groups in 2022 and 45.1% now.

So over four years, Google's ad picking has tilted further toward the higher score. It lines up with clicks a bit better than before. It does not line up with conversions any better.

Clicks cost money. Booked jobs make money. If your account is graded on clicks, a rising ad strength can look like a win while your phone stays quiet.

Why do lower-rated ads often convert better?

Pinning. Geddes attributes most of the lower-rated ads' conversion edge to it. In most of the mixed-strength ad groups, one ad was pinned and the other wasn't. Pinned ads tend to earn lower ratings, and they also tend to post higher conversion rates.

That makes sense to anyone who has pinned a headline on purpose. When you pin a price, a required disclaimer or a qualifier, you're trying to filter the click, not chase it.

Ad strength rewards variety and keyword coverage. An ad written to pre-qualify buyers works against both. So the score drops while the quality of the click goes up.

Picture a drain cleaning ad that pins "Starting at a flat service call fee" in the first headline. Fewer people click. The ones who do already know the price. That ad might get a Poor or Average rating and still beat a flashier ad with a better score. That's an illustration, not a client result, but it's the logic Geddes describes.

Should plumbers pin headlines in responsive search ads?

Pin the few things that must appear, like a price qualifier, a license statement or your service area, and leave the rest alone. Pinning lowers the rating, but it filters clicks before they cost you money. Expect a lower score, and judge the ad by booked jobs, not by the label.

A few things worth pinning if they're true for your business:

Emergency or same-day availability, if you really offer it
The towns you actually serve
A price qualifier or required disclaimer
Licensing or insurance wording your state expects

What I would not pin: every headline slot. Pin everything and Google has nothing to test, and you've turned a flexible ad into a fixed one with a worse score.

How do I test ads without letting the score decide?

Track what happens after the click. Compare ads on conversion rate, cost per booked job and conversions per 1,000 impressions, not on ad strength or clicks alone. Give each ad enough time to collect real calls and form leads, then keep the one that books work for less.

Here is a simple process:

Count only real leads as conversions: phone calls over a set length, form submissions and booked appointments. Don't let page views or button taps into the count.
Run two ads in the ad group, one pinned to filter and one unpinned for reach.
Ignore the ad strength label while the test runs.
Remember that Google will probably give the higher-rated ad more impressions, so compare rates, not raw totals.
After enough leads, compare conversion rate and cost per lead for each ad, not clicks.
Keep the winner, write a new challenger, and repeat.

Step 4 matters most. If one ad gets 63 of every 100 impressions, it will rack up more of everything. Totals will mislead you. Rates won't.

Ads are only half of how people find you, too. If your Google Business Profile is weak, you're paying for clicks while the free map listing sends the calls to a competitor. You can check yours with the free Local Visibility Score or a full Google Profile audit.

When does chasing a higher ad strength rating still make sense?

For ads you leave unpinned. Among unpinned ads in Geddes' data, CTR rose with every step up in rating, and so did CPI. Conversion rates rose slightly at each step except Poor to Average. If you aren't pinning for a reason, a higher rating generally helps.

So the honest summary isn't "ad strength doesn't matter." Ad strength predicts performance fairly well when you leave Google's system alone. It predicts poorly when you've deliberately overridden it.

The source article says only a third of unpinned ads in the dataset reached Excellent, and that an unpinned ad can reach Good with as few as seven assets. Stuffing in more headlines won't automatically get you to Excellent. Write headlines that are really different from each other: a service, a trust signal, a location, an offer.

Common questions

Does ad strength affect my Quality Score or Ad Rank?

No, according to Google's Help Center. It says ad strength isn't used to calculate Ad Rank, Quality Score or auction wins. It's described as a guide for the ad creation stage. The study's point is different: the higher-rated ad still got more impressions in head-to-head ad groups.

Is a Poor ad strength rating bad for my business?

Not by itself. A Poor or Average rating often comes from pinning, and pinned ads tended to convert better in Geddes' data. If the ad books jobs at a good cost per lead, the label doesn't matter. Judge the ad by leads and booked work.

Should I stop trying to improve ad strength?

No. For unpinned ads, a higher rating generally paid off in the study, with CTR and CPI rising at each step. Improve the score when you aren't pinning for a reason. Just don't swap a winning pinned ad for a prettier one without testing it.

How many conversions do I need before picking a winning ad?

The source article doesn't give a number, so I won't invent one. My rule: wait until both ads have a meaningful count of real leads, not just clicks. A couple of calls either way proves nothing. When in doubt, let it run longer.