CTR (Click Through Rate) will help in deciding which campaign type should be followed as higher the CTR, it’s better to go for CPM while if CTR is low , it is better to go for CPC because if you have a low CTR then you would rather only pay for the low traffic that comes to your site. If your CTR is high, then you don’t mind paying CPM – because your cost will not escalate for more and more visitors that come to your site, but will remain the same.