Admob / Adsense analysis and consulting

1 Hour job, if you are a google expert and know much about adsense and admob. How the hell is it possible that adsense banners that we display with a webview in an app (on an empty page, so no HTML content given, no keywords are on the HTML page: [login to view URL]) performs better than admob? Our info so far: Admob can be set up to show keyword specific ads (what we did by specifying an app description for each app). Also: Since Android users normally are logged in to google play, admob "knows" the user and can personalize the ads much better than in case of adsense becasue only a few users will be logged in into google via their web browser or use chrome for mobile so that google "knows" the user from a cookie or so. Nevertheless, we have low performance on adsense but incredibly bad performance with admob.... This seems strange..... Also: How can it be that an admob app has a click through rate of 50% in one month and then drop to nearly zero??????? We can't interpret the stats we get. Obviosuly there is something wrong..... But we don't know what...... The job is: Login to our accounts, analyse some timespans, and give us a hint what is wrong...... / Explain the behaviour / figures. I can provide an admob report (attached) that shows that for one app one one day we have 5000 impressions and 900 clicks (that's too much . usually lower CTRs are expected) and we earn 10$ with this app, on other days, we have with the same app again about 5000 impressions 50 clicks and get 0,11$. How is this possible? You can see this when you filter by date in Column be and compare the following days: 20.08.2013 VS. 16.08.2013 .......