The page click-through rate (CTR) is the number of ad clicks divided by the number of page views.
Page CTR = Clicks / Page views
For example, if you received 2 clicks for 250 page views, your page CTR would be 0.8%. (2/250=0.8%)
Note that this metric is only available under the "Custom" metric family tab. Find out more about the custom metric family.
