Whenever I take over an account, I often see that there are many ads in an ad group, each with a different CTR (click-through-rate.) The CTR ranges from high to low. The person didn’t delete the weak ads. That hurts the number of sales. Why?

Let’s say an ad group has three ads. The ads have 100,000 impressions each. The CTR is 5% for the two top ads and 1% for the weak ad. Let’s assume they all have a 2% conversion rate (sales rate) (in reality, the strong ads will have a higher sales rate, but let’s keep this simple.)

That means the top ads have 5,000 clicks and the weak ad has 1,000 clicks. The 2% sales rate means the top ads produce 100 sales and the weak ad has 20 sales.

If the weak ad had been deleted, its 100,000 impressions would have gone to the two top ads, thus producing 80 additional sales. By keeping the weak ad, the campaign lost 80 sales.

Look at your ad groups. Create four or five ads (to test various ads). When they reach 1,000 impressions, compare the CTRs. As a rule, I don’t keep ads that have a CTR lower than half of the top ad’s CTR (i.e., if the top ad is 2%, then no ad should be less than 1%.)