CPC Cookie Policies

Length of time a Paid UU should be Cookied

[mdisanto10]

I would like to know what is being used as "industry standard" to cookie users that you pay for in a CPC campaign.

For example, do you cookie someone for 30 days and determine that any transaction on your site resulting from that paid visitor is attributed to said CPC spend? Is it less than 30 days, more than?

Obviously the length of time you decide to cookie someone can significantly impact CPC efficiencies: cookie someone for too long and you won't see the true effect of the search campaign but don't cookie someone long enough and efficiencies against a particular medium will look awful

Any advice/experience you can share is most appreciated.

Thanks :)