I was interviewed earlier this week by Gord Hotchkiss, president of Enquiro, for an article on MediaPost's Search Insider about click fraud. "The Elusive Click Fraud Issue: Google's Side Of The Story" provides a look at some of the major issues in this area, and has a bunch of useful information for anyone interested in really understanding click fraud and how we manage it at Google. It also reiterates and clarifies some of the facts around metrics I discussed in my last post.

I was glad to see that the article covered some of the significant problems with third-party estimates – for example, a frequently-cited study from Outsell is debunked – and it also highlights how what we do at Google with respect to fighting click fraud may be considerably different from what is done at our competitors.

One part of the article which a few people asked me for further explanation about was the example of an advertiser with a $100K per month budget. The article states that it "assume[s] that the clicks this advertiser receives are representative of the total Google network." As such, it's clear that this is a hypothetically constructed model of an advertiser meant to scale the dynamics of our network into smaller dollar figure terms, to make them easily understandable. So it does not represent the experience of a typical advertiser. Why doesn't it? One of the most significant reasons that it doesn't represent a typical experience is because the vast majority of advertisers are likely not actually affected by undetected click fraud. Our reactive refund figures are based on those who are, who also write into us for investigations. So the percentage amounts refunded to that much smaller group of advertisers can obviously not be extrapolated to a much larger set of advertisers who are not affected by click fraud to begin with. Remember, all network-wide stats are averages, and every advertiser is unique.

Gord has spent the time to understand this well, and the article is definitely worth a read. I'm happy to see that we're making progress in terms of furthering understanding on both the science and accounting of this issue. I also want to thank everyone who has been asking questions on e-mail and on this blog and others. I'm looking forward to continuing our dialogue.

Update 12/18: Gord has posted some additional notes which never made it into the article on his blog.