Google announced this important notice just this past week:
Starting today, we will be updating how we report 1-10 Quality Scores for keywords [https://goo.gl/c4Oi7]. This update only affects reporting. There is no change to ad serving such as how auction-time quality signals affect Ad Rank and CPC. The most significant part of the change is that keywords without traffic will now, by default, receive a score of 6, and Average for the three components of Quality Score. Once keywords gather enough impressions, scores will update about a day or so later.Behind the scenes, this change will allow us to simplify some of our core systems, letting us focus our attention on improving reporting accuracy for keywords with traffic.
This could be good or this could be bad. Understand that AdWords quality score impacts the price you pay to get into the AdWords auction and affects the price to appear on the first page of the search results. Although the statement seems like an improvement – rating keywords without traffic to a 6, to me this seems only a cosmetic improvement.
The truth is that Google knows from other advertisers already, what the quality score typically is on a keyword phrase, but now it appears to be waiting for your program to run to allow for the quality score to be more indicative of other factors that may impact your own personal score; such as landing page and ad text.
My personal feeling is based on other news that the cost per click had decreased overall for Google AdWords based on the impact of mobile activity that this is not an innocuous update but rather a strategic push to boost profitability for Google across all devices. We may not see of understand yet this change to quality score yet, but will certainly see the results this next month.