In today's world, most SEM Gurus play the quality score game with Google and to some extent Yahoo. However, in order to impress a client or get kudos for a really innovative idea to improve CTR% or conversion, we are forced to some sort of A/B test, Ad multivariate tests and sometimes Day-parting (with the help of analytics). Typically speaking, one would think that all of this testing would wreak havoc on our goals for high Google Quality Score. Well, after a bit of thought and a quick call into Google, I can confirm that it's not as bad as we all may think it is. Let's discuss.
Day-parting DOES NOT AFFECT overall Google Quality Score because Google keeps the CTR% history. However, day-parting could backfire on you if the CTR% for that specific time is lower than it's original full-time running. So it's important to use analytics to verify when is the best time to segment the day parting.
Pausing & Deleting of Keywords:
At first, I assumed this was a no brainer that it would affect quality score, but oddly enough according to Google the deletion and/or pausing of a particular keyword/search term DOES NOT AFFECT Quality Score, because there is no loss of performance history and hence keeps it's own Quality Score.
Quality Score & Ads/Creatives:
When I attended the SES NY conference in April, 2007, one of the presenters mentioned that when testing Ads on Google, it's important to not change the Ads too much because you will lose history and eventually Quality Score. However, it's importance to note what really effects quality score at the Ad/Creative level is any change made to the landing page of a Destination URL field. (Note: This is different than losing performance stats that get recycled when making a change to any of the Ad fields) To back up my claim, here's a real example from Google regarding an inquiry I had made about a past client of mine. "As long as the landing page of the Destination URL is not changed, merely adding additional tags to the URL will not affect your Quality Score or average cost."
So, in a SEM-nutshell, the skepticism of on-going testing (day parting, deleting/pausing of keywords and Ad Variations) does not hurt the ongoing efforts of Google quality score. Frankly, I was a bit surprised that Google continues to capture of history on all of these areas. I have to admit that I am impressed with Google's dedication to allowing it's customers test and improve performance of their keywords/campaigns, etc... Let's just hope that neither of these testing elements change in the near future, especially since it's getting more expensive everyday to compete in the space.