Click fraud: are advertisers sufficiently protected?

Even if Google’s characterization is correct, Google’s “reasonable


The Pay Per Click (PPC) -- Cost Per Click (CPC) search advertising model is “inherently vulnerable to click fraud,” so says a court appointed expert, Dr. Alexander Tuzhilin.

Tuzhilin, NYU Professor of Information Systems, filed a 47-page court-requested analysis of the mechanisms underlying search engine PPC-CPC ad models, and of Google’s invalid click detection efforts, as part of the ongoing Lane’s Gifts v. Google click fraud case.

I present excerpts of the document in “Court expert on CPC model: ‘inherently vulnerable to click fraud’.”

Google characterizes Tuzhilin’s report as “a validation of what we have said for some time about our work against invalid clicks.”

Even if Google’s characterization is correct, Google’s “reasonable” efforts against click fraud are apparently not sufficient to fully protect advertisers against invalid clicks, or click fraud, according to Tuzhilin.

Tuzhilin’s detailed, scientific, and seemingly unbiased, analysis of the PPC – CPC Internet advertising payment method asserts that the model is “inherently vulnerable to click fraud” and puts forth the difficulties of policing such a model:

between the obviously clear cases of valid and invalid clicks, lies the whole spectrum of highly complicated cases when the clicking intent is far from clear and depends on a whole range of complicated factors…this intent (and thus the validity of a click…) cannot be operationalized and detected by technological means with any reasonable measure of certainty…

given a particular click in a log file, it is impossible to say with certainty if this click is valid or not in all the cases. This means that

It is impossible to measure the true rates of invalid clicking activities, and all the reports published in the business press are guesstimates at best.

Tuzhilin repeatedly stresses the inherent difficulties of identifying, and combatting, click fraud:

Conclusions about the performance of invalid click detection methods.

As a scientist, I am accustomed to seeing more direct, objective and conclusive evidence that certain methods and approaches ‘work.’…

It is hard for me to arrive at any definitive conclusions beyond any reasonable doubt…that Google’s invalid click detection methods ‘work well’ and remove ‘most’ of the invalid clicks—the provided evidence is simply not hard enough for me, and I am used to dealing with much more conclusive evidence in my scientific work.

The concluding paragraph of Tuzhilin’s report, therefore, is qualified by the scientific research which precedes it.

Tuzhilin’s concluding paragraph, which may serve to support Google’s position in the Lane’s Gifts v. Google click fraud lawsuit, says:

In summary, I have been asked to evaluate Google’s invalid click detection efforts and to conclude whether these efforts are reasonable or not. Based on my evaluation, I conclude that Google’s efforts to combat click fraud are reasonable.

Prior to his case-related conclusion, however, Tuzhilin warns:

Finally, the measures…are only statistical measures providing some evidence that Google’s filters work reasonably well. This does not mean, however, that any particular advertiser cannot be hurt badly by fraudulent attacks, given the evidence that Google filters ‘work.’ Since Google has a very large number of advertisers, one particular bad incident will be lost in the overall statistics. Good performance measures indicative that filters work well only mean that there will be ‘relatively few’ such bad cases.

Tuzhilin also qualifies Google’s “Click Quality” team efforts:

Since its establishment in the Spring and Summer of 2003 the Click Quality team has been developing an infrastructure for detecting and removing invalid clicks…Currently, they reached a consolidation phase in their efforts, when their methods work reasonably well, the invalid click detection problem is ‘under control,’ and the Click Quality team is fine tuning these methods. There is no hard data that can actually prove this statement.