Been testing keyword vs. keyphrases over the last month. I posted the data to the group on goofbucket.com. But thought I would also snippet here.
I started with (2) two coupons one from google adwords for 25.00 and the other from live adcenter for 50.00. I set both accounts to spend the 25.00 over a one month cycle, at the spend of .05 per click. Very low but it's not clicks I care about for this test.
Impressions are the target for this test. I got 62,000 impressions with the keywords women, meet, share, and find, on google with 490 clicks. On adcenter (live), same ad with the same keywords I got 120,000 impresssion with the full 500 click that the buy allowed. Now keep in mind live is much smaller then google number of impressions is skewed however it is the keywords that interest me.
At the half way mark I change the keywords to key phrases, example I combined meet, and women to the keyphrase, 'meet women' in the second half. This is when the majority of the impressions and clicks came in.
Begin reading the full series of these reports on goofbucket.com but I will still post snippets of all studies here, as I do them.