Now that Google is eliminating Position Preference (http://adwords.blogspot.com/2011/04/adwords-position-preference-feature-is.html) I’m forced to weigh my alternatives to a wonderful feature that had significantly lowered both my cost per click AND cost per conversion.

Please keep us up to date if you try CPA again or another method. (And if you post results elsewhere, perhaps a reply to this column as well to help us track it.)

Thanks again.

I am going to point to this article in my book. http://ppc-optimization-secrets.com. Please let me know if this is an issue.

I’d like to post your article on my website http://www.CPABenefits.com and would like permission to do so.

As I say in the post “It wouldn’t be wise to draw any sweeping conclusions from one test with a limited amount of data.”. So I am not claiming it is a rigorous, statically valid result. Even if it was, it might not be applicable to other products.

The number of conversions used is commercially sensitive.

Thanks for sharing your data about the efficiency of CPC vs CPA within Google adwords.

Unfortunately we can’t really reach a statistically significant conclusion here because you didn’t ran each campaign simultaneously (this is a bias in your experimental design due to potential variations in time, numerous seasonal effects etc).

Furthermore i think it would make sense to know how many conversions you measured as a difference of 6.6% between CPC and CPA requires a good confidence interval in order to be really accurate.

Don’t get me wrong here, your article is great, i just wanted to share with you my feedback because i know that sometimes reaching conclusions too fast may result in significant losses.