A year ago we tried using admob to test different icons for a game of ours. The idea was to see if any particular icon would get a significantly higher CTR than the others (which we hoped would mean it'd perform better on the app store). The results were inconclusive. At first, the CTRs were very close together, and so low that I suspect they were mostly accidental clicks. Then, after a couple of days, the differences widened so much (even for very similar icons) that we suspected admob was randomly trying different channels/demographics/devices/whatever to optimize each icon, to the point where the data was useless. I was hoping someone here has done the same thing, and could share some pointers on how to use ad networks for A/B testing, as well as which network is best suited for this purpose?
Ive used facebook CPM campaigns and have been happy with the results. Use the same title/description and just change the icon.