Google has announced a change in its keyword quality score, though not a significant one. The search engine said that they have updated the way how the Google AdWords reporting shows the Quality Score for your keywords.
Google however added that the update won't have any direct impact on Google ads, their rankings or CPCs. This is just a reporting change on the front end and will not affect the existing ranking algorithm of your AdWords ads.
Google further said that the most visible change advertisers may see is that new ads with no impressions will default to a quality score of 6 and then once Google has data, the score will be updated in about a day or so later.
See what Google said in its blog post:
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.
You needn't to worry if you see changes in your quality score.- Google AdWords Changes Quality Score