Google announced today that it is making some changes to how reporting works in AdSense accounts. The company is updating the way certain data is shown.
AdSense product manager Matt Goodridge explains on the Inside AdSense blog:
As you may know, your earnings at the end of each month currently reflect the amount you've earned less any deductions for invalid activity. This is a step we’ve always taken to ensure advertisers are not charged for such activity. Until now, however, clicks and impressions associated with this activity still appeared in AdSense performance reports. Starting May 1st, we'll remove those associated clicks and impressions to address this discrepancy and provide you with the most accurate reporting.
So what does this mean for your AdSense account? First and foremost, this change will not impact your earnings in any way. In most cases, removing the invalid activity from your reports means you can expect to see a slight decrease in clicks and impressions, causing a slight increase in CPC (cost-per-click) and RPM (revenue per thousand impressions). The clicks and impressions that we’ll no longer show in reports include activity like accidental clicks, so metrics like your CTR (clickthrough rate) will more accurately reflect your site's performance. You might also see a more noticeable difference in your AdSense reporting when compared with your own account statistics measured through other tools. Please note that this change won’t affect the way we screen for invalid activity.
Reports for dates from before May 1st will not be affected by the changes.
A couple weeks ago, Google announced changes to the Terms and Conditions for Adsense. More on that here.