Googles Click Quality Team have just published a report "How Fictitious Clicks Occur in Third-Party Click Fraud Audit Reports" which I shall be digesting this evening and from first review am likely to agree with quite a lot of.

One of the simplest metrics we use to spot the anomalies is to compare the effectiveness of a number of engines in terms of the number of visitors they register as valid clicks against what we register ourselves in terms of actual visitors. This is a pretty good direct comparison of the effectiveness of their clickfraud detection systems based around the most obvious types of attack.

So, although I am not known for leaping to Google's defence when it comes to Pay Per Click advertising (UK DST you know precisely why) their detection isn't anywhere as bad as some of the other search engines, and in fact it has been making noticeable improvements recently. However any % improvement is usually offset by the higher traffic volumes Google generates.

The zero line is somewhere around what we regard as the norm, anything above is unacceptable. The further below the zero line the more the search engine is airing in favour of the advertiser, and the more level the lines the more consistent their detection.

Keep an eye on this site as we will be publishing our own agency side review of the clickfraud issue in the next week or so with some sector based analysis of the main UK Pay Per Click  Search Engines.