While doing PPC , What would be the best CTR , Is CTR counts for a single keyword or for a Ad Group keywords ?
CTR directly influences your quality score. The QS is what determines where your ads rank and how much you pay. It is calculated for each keyword and is a measure of your CTR compared to competitors, normalized by position. So, try to increase your CTR to get a QS of 10. You can get a QS of 10 with a CTR of 8% just as you can with a CTR of 2%. It just depends. Learn more.