What is Quality Score?
Quality Score is a rating Google assigns to every keyword in a search campaign. It is expressed on a scale from 1 to 10 and indicates how relevant and useful your ad is compared with other advertisers bidding on the same keyword.
The higher the Quality Score, the lower the cost per click and the better the ad position. It’s one of the mechanisms through which Google rewards ads that are useful to the user, not just those with the highest bid.