According to a report by Click Fraud Index, Click Fraud rate is actually lower than the widely assumed level of 20% to 30%. The report shows that the average overall Click Fraud rate is 13.7 percent.
However, the rates vary with search engines. On Google and Yahoo! the rates are still lower at 12.1 percent. This rate rises to 21.3 percent for the second level and 29.8 percent for third level search engines. The report is based on data from those who are part of the Click Fraud Network and are audited by Click Forensics, a clisk fraud auditing company.
This report adds to the dispute between search comapnies and advertisers about the true click fraud figures. How you look at this report depends upon which side you are on.