We would like to build an aggregate paid search page that pulls in data from AdWords and Bing. The snag is trying to report on impression share across both platforms. We can create a custom metric that takes IS (Bing) + IS (AdWords) / 2 = Aggregate IS, but having that as an aggregate metric would be ideal.
Aggregate Metric for Impression Share (AdWords/Bing)
a1: most a2: medium a3: no