The click-fraud debate is as polarized as they come. While it is imperative that adservers play down click-fraud estimates, click-fraud firms need to justify their raison d'etre--and hence, the fees they charge. With so much bias and uncertainty, advertisers should focus more on their ROI than anything else.

The business product manager for Trust & Safety at Google, Shuman Ghosemajumder, is responding to two third-party press-releases about the rising rate of click-fraud. While one press-release cites an 0.5% increase in click-fraud over the last year, another press-release claims that click-fraud cost advertisers $666 Million in 2006.

In the first part of his series on click-fraud, Why Third Party Click Fraud Rates Don't Add Up, Ghosemajumder cites five reasons why click-fraud estimates often don't add up. He writes:

1. Many third-parties have not even counted clicks properly: [...] We found serious flaws in [third parties'] counting of clicks [...] They were making basic counting mistakes and inflating the number of clicks by an average of 40%. [...]
2. Inflated click counts result in even more inflated "click fraud" estimates: This over-counting problem results in an even more dramatic inflation of click fraud estimates [...]
3. Even if they fixed those problems, they're not actually measuring click fraud
4. Industry metrics (in any area of our business) are not necessarily the same as Google's metrics
5. ROI on the content network is the same as it is on search

[...] The key point here is not that their numbers are "too high". The point is that their data collection methods are inherently flawed and any resemblance their numbers could have to reality would be coincidental.

Ghosemajumder's point are valid ones. Indeed, he begins to elaborate on them in a follow-up post. However, both Google and the click-fraud firms have a vested interest in influencing estimates. As Andy Beal points out:

If most of you don’t trust numbers supplied by Google, can you trust numbers supplied by a company that has a vested interest in seeing click fraud grow? They may counter that they sampled 3,000 advertisers, but surely the sample set is biased. If you walk into a hospital and ask 3,000 patients, “Who here is feeling unwell?”, wouldn’t you expect a biased result?

So where does that leave us? It leaves us desperate for a third-party audit of click fraud, completed by a group that has no skin in the game. In the meantime, let’s assume click-fraud is somewhere between 0.2% and 14.2%.

Indeed, the click-fraud debate seems destined to continue. At the end of the day, if your conversion rate has meant that new revenues exceed advertising expenditures, then you're probably doing okay.