Last year in december, Google claimed that Click Fraud Rate Less than 2%. However, Google has released a click fraud report which informs that click fraud rate is less than 0.02%.
Google AdWords Blogspot reports:
Our Click Quality team investigates every inquiry we receive from advertisers who believe they may have been affected by undetected click fraud. Many of these cases are misunderstandings, but in most cases where malicious activity is found, the clicks have already been filtered out (and not charged for) by our real-time filters. Because of the broad operation of our proactive detection, the relatively rare cases we find of advertisers being affected by undetected click fraud constitute less than 0.02% of all clicks.
Shuman Ghosemajumder, business product manager for trust & safety at Google says, “We've been working to be more transparent and informative on the issues related to click fraud. Recently, this metric has been something advertisers have specifically asked for and we agree that is useful in describing the scope of the problem. Further, it is something we measure and use to monitor the performance of our click fraud detection systems.”
This figure will surely invite a lot of critical reviews. Danny Sullivan at Search Engine Land finds it hard to believe that the rate is so low. He says, “What about the main mystery figure that I and others have been wanting — the detected click fraud rate, the percentage of clicks that got past all Google filters and would have cost advertisers money, had they not raised an alarm? The detected click fraud rate is less than 0.02 percent of all clicks. To use Google's term, this is the rate for "reactively identified invalid clicks" — refunds given after advertisers asked for an investigation.”
Search Engine Land has a good post on it.