Google Optimization Scores: A study on the performance of Google Ads

The Optimization Score (OptiScore) from Google Ads has sparked discussions in digital advertising since its introduction. At Google Marketing Live (GML) 2024, an interesting statistic was presented. An increase in the OptiScore by 10 points improves the conversion rate by 15%. This figure triggered many discussions, as there are concerns about the relevance of this metric for performance. Some question whether the OptiScore truly reflects the performance of a Google Ads campaign. A study examined 17,380 Google Ads accounts to evaluate the relationship between OptiScore and campaign performance.

The Optimization Score is a metric from Google that indicates how well a campaign is optimized. The score is displayed as a percentage and ranges from 0 to 100%. A score of 100% means that, according to Google, the account has reached its full potential. In addition to the score, Google provides recommendations that can help improve the score when implemented.

The study examined three central questions:

1.Are there performance differences between accounts with OptiScores above 70 and those below?

2.Do results improve when advertisers accept Google's recommendations and thus achieve high OptiScores?

3.Does the advertising budget influence the OptiScore?

The study analyzed accounts that had been active for at least 90 days. The monthly advertising budget was between $500 and $1 million. It considered both e-commerce and lead generation accounts.

The data showed a clear connection between high OptiScores (over 70) and better performance across most metrics. These included Cost per Acquisition (CPA) and Return on Ad Spend (ROAS). Accounts with OptiScores of 90-100 outperformed those below 70 in ROAS by 186%. The Cost per Acquisition was also lowest in the group with the highest OptiScores.

Interestingly, accounts with an OptiScore below 70 performed better in two categories: conversion rate and click-through rate (CTR). This indicates that a lower OptiScore does not necessarily lead to poorer performance, especially when CTR and conversion rate are critical factors.

Summary

• Accounts with OptiScores of over 90 have the best ROAS and the lowest CPA values.
• Accounts under 70 surprisingly performed better in terms of conversion rate and CTR.
• The OptiScore has no significant impact on the cost-per-click (CPC) or the CTR.

A central theme in the discussion around the OptiScore is the skepticism towards Google’s recommendations. Many advertisers suspect that these recommendations are more aimed at increasing ad spend rather than improving campaign performance. Nevertheless, the study showed that accounts that accepted Google’s recommendations generally performed better.

Only 5.5% of the accounts examined adopted Google’s recommendations. Among these, those with OptiScores of 90-100 achieved the best results. However, there is evidence that many advertisers improved their OptiScores without following the recommendations. This suggests that rejecting recommendations does not automatically lead to poorer performance.

The data shows that advertisers performed best when they were actively working on their accounts. It did not make a significant difference whether they fully adopted Google’s recommendations or not.

Summary

• The majority of advertisers (95%) do not accept Google recommendations, but still achieve an improvement in the OptiScore.
• The best results were achieved by accounts that both accepted Google recommendations and actively optimized their campaigns.

Another aspect of the study was the impact of the advertising budget on the OptiScore. Contrary to expectations, the analysis showed no clear connection between budget size and OptiScore. Accounts with high budgets did not automatically achieve higher OptiScores, and those with smaller budgets often produced similar results.

The budget only played a role in the lower OptiScore ranges. When an OptiScore increased from below 70 to above 70, costs went up. However, this effect disappeared once the OptiScores reached the higher ranges.

Summary

• The advertising budget has no significant influence on the OptiScore.
• Higher expenditure does not necessarily lead to a better OptiScore or better performance.

Although the OptiScore does not directly influence the auction process, it serves as a useful health indicator for account performance. Advertisers should not consider it a primary KPI but rather use it as a guide to identify optimization opportunities.

Best practices for using the OptiScore:

• Stay active: Those who carry out regular optimizations often achieve higher OptiScores and better campaign performance.
• Carefully review recommendations: It is wise not to blindly accept Google’s recommendations, but also not to completely ignore them. Many recommendations, especially those related to campaign hygiene, such as cleaning up negative keywords or improving conversion tracking, can be helpful.
• Prioritize: Use the OptiScore to identify where optimizations are most urgently needed. Focus on areas that have the greatest impact on your campaign goals.

The study shows that the OptiScore can be a useful tool for assessing account health. However, it should not be the sole success indicator for Google Ads campaigns. A high OptiScore often correlates with better performance in ROAS and CPA, but there are exceptions. Some accounts with lower OptiScores still achieve good results in conversion rate and CTR. Ultimately, advertisers should use the OptiScore as one of many indicators to continuously optimize their campaigns.