Quality Score
Google's 1-to-10 rating of ad relevance, expected click-through rate and landing-page experience.
Quality Score is Google's 1-to-10 diagnostic of how relevant your keyword, ad and landing page are to a search. It is built from three parts: expected click-through rate, ad relevance, and landing-page experience.
It matters because a higher Quality Score buys a cheaper click and a better position at the same bid, so relevance works like a discount. You raise it by tightening the match between keyword, ad and page: granular structure like single keyword ad groups, sharper ad copy, and a landing page that delivers on the ad's promise.
Treat it as a diagnostic, not a target: it points at the weak part of an ad group so you know what to fix.
Put the number to work: the break-even ROAS calculator turns your margins into the ROAS you need, and a free Due Diligence Audit checks whether the figures you see are the ones you are getting. Back to the glossary.