Google Adsense has stopped showing invalid clicks and impressions in performance reports from 1st May ,2013.In an official blog post google announced that they are removing the invalid clicks and impressions from Adsense performance reports to increasing the accuracy of AdSense reporting.As we know ,untill now Google Adsense was also showing invalid clicks and impressions in performance reports but Adsense was not awarding any credit to publishers.Previously , if you received a click on your Adsense ad which was flagged as invalid by Adsense then that click also appeared in Adsense performance report but CPC for that click became zero.But now, if you receive any click on your Adsense ads which is flagged as invalid then it will not appear in your performance reports.
How it will affect your Adsense earning-
After this update your CTR will decrease slightly and your CPC and RPM will increase slightly because zero earning clicks (invalid clicks)and impressions will not appear in your account.However it will not affect your Adsense earning.
After this update you will able to see your real CPC and RPM in Adsense performance reports.
The biggest disadvantage of this update is that now you can not rely on Adsense performance report to determine any invalid click activity or Click Bombing attack on your Adsense ads.For example if a visitor deliberately clicks 100 times on your Adsense then your Adsense performance report will not show those 100 clicks and you will be completely unaware of this activity.As you know ,Adsense is very strict against invalid clicks and impressions so you may lose your Adsense account due to invalid clicks.However you may use your own programs,Google Analytics or Statcounter for tracking clicks on your Adsense ads.