Your Quality Score is very important, but your primary and most valuable goals should influence your account optimisation.
The Quality Score may not always reflect your goals and it may just be used as a performance indicator.
The CTR (Click-through rate) is one of the most important factors of the Quality Score, however, increasing your CTR does not necessarily increase your conversions.
A higher CTR may increase your overall costs, but if your conversions did not increase, your cost per conversion is likely to go up.
Optimisation
An example of a keyword with a low Quality Score, 4/10.
In this campaign, conversions and cost per conversion are good, and therefore the keyword does not need optimisation just to get a better Quality Score.
An example of a keyword marked ‘Rarely shown (low Quality Score)’ with a low Quality Score, 1/10.
In this campaign, impressions, clicks, and cost per conversion are good, and therefore the keyword does not need optimisation just to get a better Quality Score.
Historical Quality score
The Historical Quality Score is an aggregated estimate of how well a keyword has performed overall in past ad auctions.
The Historical Quality Score shows you the last known Quality Score for your reporting period.
Compare days or months to analyse your historical Quality Score.
In this example, the Historical Quality Score was 5/10 in October and 7/10 in September. In October, the Quality Score decreased by -2/10,
(-28.57%). Some changes in October might have contributed to the drop.
In this case, it is necessary to optimise the Quality Score.
Change History
The ‘Change History’ shows all changes made during any given period, and it helps you to understand what changes may have affected the Quality Score.
Conclusions
Optimise your account for a better Quality Score is a very good practice.
However, if your Quality Score is not your primary goal, and your campaigns are converting well with low Quality Score keywords, do not optimise your keywords just to get a better Quality Score.
Extract from my Book ‘Making Google Ads Work’.