Google on Tuesday pooh-poohed the efforts of certain critics who, it said, have hyped the issue of click fraud.

Google accused three auditing firms that sell click-fraud detection services to advertisers of relying on flawed technology, reports the Financial Times. A Google report said its examination had "discovered some basic engineering and accounting issues across the industry" that have led to "dramatic overestimation of click fraud rates by these firms." Those firms' research is used by some advertisers to challenge billings from Google.

Two key findings of the report "explain the fundamental flaw we have seen in all of the reports we examined - fictitious clicks: events which are reported as fraudulent, but are never recorded or charged as ad clicks by Google", according to a post in the AdWords blog.

For one, auditing firms counts such fictitious clicks when a surfer browses more deeply into an advertiser's site and then hits the back button, presses the browser reload button when on the landing page or opens a new browser window and causes a reload of the landing page, CNET quotes a Google spokesman as saying.

"Fictitious clicks due to conflation across advertisers and ad networks" - that is, "the counting of one advertiser's traffic in another advertiser's report, even if the
advertisers span different ad networks," is a second key finding of the 17-page report (pdf) and arises from a faulty tracking of cookies.

"One often-used consultant implements the cookie in such a way that clicks on Yahoo ads can be counted as clicks on Google ads, and vice versa," according to the AdWords blog, which provides further explanations on the topic.