How Accurate is Google AdWords?

[mandy]

This web analytics expert asks how accurate Google AdWords is and how the company handles possible errors...

Given that such a vast amount of our money goes to Google on the say-so of a single web analytics system, it's extremely important to know how accurate that technology is.

It is well established that it is impossible for any web analytics technology to be 100 percent accurate. Most systems are accurate to within 95 percent...

My personal experience is that the accuracy of the billing system in Google AdWords varies. I run PPC campaigns for clients, and I always check Google's numbers with what our own software, InSite, says. Since we always run a unique tracking code on every Google ad, this is fairly easy. I have disputed numbers with Google several times over the last few years...

full article: http://imediaconnection.com/content/11019.asp