I have two ads in several adgroups which seem to be drawing traffic irrespective of ctr. In other words the ad with higher ctr (2.1%) is being served 1% of the time, whereas the ad with lower ctr (1.9%) is being served 99% of the time. These ads have been running for a long period and have received substantial traffic over time. I am thinking that maybe G somehow uses conversion rates to increase quality score for those of us that adjust bids based on conversion costs. Is anyone else experiencing this? Does anyone know if ad quality score takes into account conversion rates?