Definition: Invalid clicks are clicks on AdSense ads that Google suspects may be fraudulent. Most of these clicks are caught by automatic filtering from Google. However, a small percentage of invalid clicks do result from human investigation at the request of the advertiser.
Advertisers are not charged for invalid clicks, and AdSense publishers are not paid for them.
According to Google, invalid clicks usually account for less than ten percent of all traffic. Google also claims that the rate of invalid clicks is higher than the rate of actual click fraud.
