Google announced in June that publishers will be able to see the invalid activity deductions caused by invalid traffic on the Adsense payments history page, starting with May’s payment history. I checked my estimated earnings for July and noticed that $5 was deducted, less than 1%.
If you notice deductions in your account too, you should be worried ONLY if over 30% of your earnings were deducted; else, I see no reason why you should worry so much about it.
This deduction is mostly caused by invalid activity on your site, such as accidental clicks, clicks from bots etc
If there is a large difference between your estimated earnings and your finalized earnings, make sure to review these tips.
To prevent invalid activity on your site, pay special attention to your site design and traffic acquisition. If you see unusual levels in invalid activity, I encourage you to notify Google by using the Invalid Clicks Contact Form.
Any deduction from your Adsense account?