As I suspected, the amount of Click Fraud is not as high as some industry analysts claim (~25-30%); it actually turns out to be around 14% according to a study by Click Forensics.

The click-fraud rate is around 14 percent, on average, less than the oft-suggested 20-35 percent, according to a new report from Click Forensics, which released its first Click Fraud Index in March, reports TechWeb.com. The monitoring firm said more than 90 percent of click fraud originated within the United States and Canada.

My experience with clients shows even less, more like 10%.  It probably depends on how you define click fraud and what industry we’re looking at as it’s worse for some clients than others.