jeremy_goodrich - 6:42 pm on Jun 23, 2003 (gmt 0)

Good points, agreed. What you need to do, imho, is to track *everything* and then analyze the macro trends that impact the biggest portion of your ad spend first, and then go down the list, till the analysis will take too much time to justify either positive or negative ROI.

At that point, if you are automating some aspects of the process, then the analysis will not cost anything in terms of real dollars spent (as it will be part of a package or what not) however, if it is something done by hand, then you need to be careful with your time versus your return.

It's a matter of ROI & dependent on your adspend analyze the 'big ones' first, and then go down the food chain.

As for the 'statistically significant' bit of your post, I would say that you need to determine your desired CPA or CPO before you start doing any sort of ROI analysis - because if you don't assign a value (even if you adjust it later) then you have no idea if it was 'positive' or 'negative' ROI.