[jonknee]

It doesn't seem bad, but the CPA doesn't really matter if they can't fill. If Apple is leaving money on the table that means they just don't have the impressions (which is believable, you don't see iAds in a lot of apps).

It could also be a targeting problem (they don't know who is most likely to download), but iOS users are pretty app happy so I would imagine this is the easiest type of ad to convert with. Apple has a huge advantage here as the control the whole ecosystem and are the only ones in the world who can optimize the App Store. Just 25 installs after 1,702 taps for a free app with good reviews seems depressingly low.