A relatively new Google AdWords advertiser who has revived an older campaign ran into a few problems and sought some answers in the High Rankings Forum. How does Google measure quality score? What data is used to determine the position?
There is a good amount of feedback on the thread that I felt would be worth sharing.
As far as old campaigns go, if the account has a really bad history and not-so-good quality scores, it's better to close that account and start from scratch rather than to revive an old account and have Google use that history against you.
After all, as member Jeremy Brookins says, "if you move your keywords, Google continues to consider that keyword's previous history. HOWEVER, it also will weight in an expected performance of the new adgroup/ad/landing page, which can be a good or bad thing depending on your previous performance."
Yes, as moderator Jonathan Hochman adds, previous performance is important, and history of the last three months seem to have the biggest impact.
Jeremy also adds that position is accounted for in many ways. A variety of factors influence position of ads:
According to Google, the things taken into account for position are Max CPC, CTR, Keyword to Ad copy relevance, & Keyword to Search relevance. When you're talking minimum CPC: it's CTR, Keyword to Landing Page, and Keyword to Ad. I think weighted in that order.
The other things that obviously are accounted for are bounce rate, because Google wants to maximize profitability.
Forum discussion continues at High Rankings Forums.