For yesterday I decided to re-enable the auto-refresh again, just to investigate any changes.

So, as expected the Impressions were going up to over 80k (35k before) and CTR dropped massively back to 2.81% (6.8% before). The CPC stays equal at around 0.03 per click.

The overall revenue was slightly raised, but not as much as it was before the experiment - it may have happened, that the enabling of the refresh was not timed well with the admob statistical data collection, so I will see tomorrow if that had any impact. Yes, I get backfilled by adsense again which - surprisingly - had no influence on the CPC.

The overall amount of clicks is not really much more. 2.279 (yesterday) instead of 2.188 (day before). So the auto-refresh itself does not do that much to your actual click amount - it is almost the same, so IF CPC would raise with CTR (which is not confirmed) you should definitly go for a higher CPC instead of Imps.

CTR or Impressions
Conclusion 1:

So, even when there are some hints, that higher CTR does influence the CPC on admob also, I still believe strongly, that admob just do not have enough of high paying CPC ads .. OR .. they are given away to other devs with even more CTR (which is possible). My CTR was at up to 7% but I also have some apps with very low Imps and therefore a CTR of up to 20% and they DO get very high CPCs (up to 9ct/click)

Conclusion 2:

I've made this experiment with an manually triggered refreshment time of 10 minutes (instead of 2) - and I cannot tell exactly if that was simply a bit too much and it really may be interesting what would happen with a refresh of 5 minutes.
Those numbers will NOT equal for all games, it will depend on how players use your game and many other factors, so this post is not intended to tell you the "best way" it is just an experiment I've made to clear up some myths (or facts) about CTR and anyone is welcome to have his/her own opinions about it.