Use relevant keywords or else you will pull down the quality index for your ad.

You should split ad groups so that lower quality keywords dont bring down the quality score of your higher rate keywords.Summary Ad quality is the relevance of an advertiser ad to a user Campaigns, users and performance affect ad quality Keywords, ad copies and queries a the key areas. Quality index can help you raise your quality score and improve ad relevance.Richard Simms, Anchor Intelligence, said there is a quality score for both advertisers and publishers.