Does Google Ads Optimisation Score Really Improve Performance?
Google Ads optimisation score has become one of the platform’s most debated metrics. Google positions it as a useful guide to improve campaign performance, suggesting that increasing your optimisation score can lead to better conversion results. But is that actually true in practice?
A recent study by PPC software company Optmyzr analysed over 17,000 Google Ads accounts to explore whether optimisation score genuinely impacts campaign performance. The findings were fascinating — and they reveal a much more nuanced picture than Google’s headline claims.
In this article, we’ll break down the study’s key findings, explain what optimisation score really means, and discuss whether advertisers should actually care about it.
What Is Google Ads Optimisation Score?
Optimisation score is Google’s rating system for how well your campaigns are set up according to its recommendations. It’s shown as a percentage from 0 to 100 inside your Google Ads account.
Google uses this score to estimate how likely your campaigns are to perform successfully. The higher the score, the more aligned your campaigns are with Google’s suggested best practices.
Typical recommendations that increase optimisation score include:
- Launching Performance Max campaigns
- Enabling the Google Display Network
- Turning on Search Partners
- Using automated bidding strategies
- Fixing keyword conflicts
- Adding assets and extensions
- Tracking conversion values
On the surface, that sounds helpful. However, the problem is that many of these recommendations are not universally beneficial for every business.
The Problem With Optimisation Score
The biggest criticism of optimisation score is simple: Google rewards actions that increase ad spend and broaden campaign reach, even when those actions may not be suitable for your business.
For example:
- Launching a Performance Max campaign can significantly increase your optimisation score.
- Enabling Display Network traffic often boosts your score.
- Activating Search Partners can also improve the percentage.
But these features don’t always produce better-quality leads or sales.
For some businesses, especially smaller lead generation campaigns with tight budgets, expanding into Display or Search Partners can reduce traffic quality and waste spend.
That creates an obvious conflict:
- What improves optimisation score may not improve profitability.
- What’s best for your business may actually lower your optimisation score.
This is why many experienced advertisers treat optimisation score cautiously.
What Did The Optmyzr Study Analyse?
Optmyzr analysed 17,380 Google Ads accounts to investigate the relationship between optimisation score and performance metrics.
To ensure fair comparisons, campaigns had to meet specific criteria:
- Running for at least 90 days
- Spending at least $500 per month
- Maximum spend capped at $1 million per month
- Included both eCommerce and lead generation campaigns
The study also considered how advertisers interacted with Google’s recommendations tab.
Importantly, advertisers can either:
- Accept Google’s recommendations
- Reject them after reviewing them
Interestingly, rejecting recommendations can still maintain or increase optimisation score because Google sees the recommendations as “reviewed”.
Key Findings From The Study
The results revealed several surprising trends.
1. Many Advertisers Ignore Google’s Recommendations
The study found that:
- 32% of accounts had optimisation scores below 70
- 19% achieved scores above 90 without accepting Google recommendations
- Only 5.5% of accounts fully accepted Google’s recommendations
That alone shows that many advertisers are sceptical about blindly following Google’s advice.
2. High Optimisation Scores Correlated With Better Overall Performance
Accounts with optimisation scores between 90 and 100 generally achieved the strongest overall performance metrics.
Google itself claimed at GML 2024 that increasing optimisation score by 10 points could improve conversion rates by 15%.
However, averages can be misleading.
The study suggests there are clear winners and losers hidden inside that headline statistic.
Why Lower CPCs Don’t Tell The Full Story
One of the study’s findings showed that higher optimisation scores were associated with lower CPCs (cost-per-clicks).
At first glance, that sounds positive.
But there’s an important reason why this happens.
When advertisers enable:
- Performance Max
- Display Network
- Search Partners
…they gain access to cheaper traffic sources beyond Google Search.
Display clicks and YouTube traffic are usually far less expensive than Search clicks because users are not actively searching for a product or service.
So yes, CPCs become cheaper — but that does not automatically mean the traffic is higher quality.
Why Conversion Rate Data Was So Interesting
Perhaps the most revealing result was the conversion rate data.
Accounts with optimisation scores below 70 achieved the highest conversion rates overall.
That’s extremely important.
It suggests that advertisers running tightly controlled campaigns often generate more qualified traffic than advertisers following every Google recommendation.
These advertisers typically:
- Avoid unnecessary traffic expansion
- Stay focused on Search campaigns
- Use tighter keyword targeting
- Reject low-quality placements
- Prioritise lead quality over scale
For many small and medium-sized businesses, that approach makes perfect sense.
A local business usually wants:
- Reliable leads
- Consistent quality
- Predictable conversions
—not maximum scale at any cost.
Why High Optimisation Scores Still Performed Well
At the same time, accounts scoring between 90 and 100 still performed strongly overall and ranked second for conversion rate.
Why?
Because large businesses often benefit from broader campaign expansion.
For bigger advertisers:
- Scale matters more
- Growth volume matters more
- Automated campaign types can unlock additional reach
Performance Max campaigns, for example, can work exceptionally well for large eCommerce brands with extensive data and product feeds.
So the study likely reflects two very different advertiser groups:
Smaller Businesses
Focused on:
- High conversion rates
- Tighter control
- Lead quality
Larger Businesses
Focused on:
- Volume
- Scaling
- Automated expansion
Both approaches can work — but they serve different business objectives.
What About CPA And ROAS?
The study also revealed:
- Lower optimisation scores had higher CPAs
- Higher optimisation scores had stronger ROAS figures
Again, context matters.
Higher CPA Isn’t Always Bad
Tightly controlled campaigns often target more competitive, high-intent traffic.
That traffic costs more.
But it may also produce:
- Better-quality leads
- Higher close rates
- More profitable customers
So a higher CPA can still be worthwhile if lead quality improves.
Why ROAS Increased With Optimisation Score
ROAS (Return On Ad Spend) improved steadily as optimisation scores increased.
One likely reason is that advertisers with higher optimisation scores were also more likely to:
- Track conversion values properly
- Run eCommerce campaigns
- Use value-based bidding strategies
Google rewards accounts that send better conversion value data.
As a result:
- More advanced advertisers naturally achieve higher optimisation scores
- Those same advertisers are often better at maximising ROAS
This may explain the correlation more than optimisation score itself.
Should You Care About Optimisation Score?
The short answer is: yes — but only to a point.
Optimisation score should never become your primary KPI.
Instead, it should be treated as:
- A diagnostic tool
- A source of ideas
- A prompt for reviewing campaign settings
What it should not become is a target you blindly chase.
When You Should Ignore Google Recommendations
You should be cautious about recommendations when:
- They reduce traffic quality
- They broaden targeting unnecessarily
- They increase spend without improving profitability
- They push automation before enough data exists
For many smaller lead generation businesses, tighter campaign control often produces better results.
When Google Recommendations May Help
Google’s recommendations can absolutely help in situations where:
- You need more scale
- You run large eCommerce campaigns
- You already have strong conversion tracking
- Your account has significant historical data
- Automation aligns with your goals
The key is testing recommendations strategically — not accepting everything automatically.
Final Thoughts
The Optmyzr study highlights something experienced advertisers have known for years:
Optimisation score is not a reliable measure of campaign success on its own.
Higher scores can correlate with better performance in some situations, especially for larger or more advanced advertisers. But lower optimisation scores can also produce excellent conversion rates when campaigns are tightly managed.
Ultimately, the best strategy is simple:
- Focus on your business goals
- Measure profitability and lead quality
- Test recommendations carefully
- Ignore vanity metrics
Google’s optimisation score can be useful guidance — but your real KPI should always be business performance, not a percentage inside the Google Ads interface.
