Recently, an independent study on click fraud detection practices of Google shows Google makes reasonable efforts to detect click fraud. The Google Blog posted the study. The report was part of an agreement of the Lane's Gifts v. Google settlement and was performed by Dr. Alexander Tuzhilin, Professor of Information Systems at NYU. You can read the 47 page report here.
"The bottom-line conclusion of the report is that Google’s efforts against click fraud are in fact reasonable. At several points in his report, he calls out the quality of our inspection systems and notes their constant improvement. It is an independent report, so not surprisingly there are other aspects of it with which we don’t fully agree. But overall it is a validation of what we have said for some time about our work against invalid clicks."
Excerpts of Dr. A. Tuzhilin's comments,
“During this project, I visited Google campus three times and interviewed over a dozen of the Click Quality team members from the Spam Operations and the Engineering groups, as well as the Product Manager of the Trust and Safety Group. I found the members of both groups to be well-qualified and highly competent to perform their jobs. Most of them have relevant prior backgrounds and strong credentials. The current set of Google filters is fairly stable and only requires periodic 'tuning' and ‘maintenance’ rather than a radical re-engineering, even when major fraudulent attacks are launched against the Google Network.”
After the recent volley of accusations and subsequent clarifications, this might just come as a relief to Google.