Google is fixing its Quality Score feature and improving quality algorithm. In view thereof the company said:

We're constantly working on ways to improve our Quality Score evaluation and provide you with more information about the Quality Score for your keywords. Over the next week, we'll be releasing two changes focusing on transparency and quality, which I've outlined below:

Transparency - Later this week, we're releasing an optional Quality Score column that shows the minimum bid for all of the keywords within an ad group as well as a Great, OK, or Poor quality label for your keyword. You can select this column by clicking 'Customize Columns' in one of your ad groups.

Quality - Next week, we're launching improvements to the Quality Score algorithm that sets minimum bids for keywords in order to improve the quality of ads that we serve to our users. These changes should make it easier for high quality ads to enter the auction while also discouraging low quality ads. First, we're improving the way that we set minimum bids for keywords where we have limited data. Second, we're improving the Quality Score algorithm to make it more accurate in predicting the quality of all ads.

If you find that the minimum bids for any of your keywords increase, making your keyword inactive for search, please consider optimizing your campaign instead of raising your maximum CPC to the minimum bid. We recommend changes such as choosing a keyword that is more specific to the product or service that you offer or editing your ad text to make it more relevant to the keyword before you simply raise your minimum bid. By improving your quality we hope to provide the highest quality ads to our users while also providing you with the highest quality leads to maintain great ROI.