Google on Friday announced that is has launched an algorithmic change to its web site ranking system in an effort to to give people the most relevant answers to their queries as quickly as possible.

Google described the change as a "big algorithmic improvement" to its ranking- a change that noticeably impacts 11.8% of the queries. This update is designed to reduce rankings for low-quality sites - sites which are low-value add for users, copy content from other websites or sites that are just not very useful, Google said. At the same time, it will provide better rankings for high-quality sites - sites with original content and information such as research, in-depth reports and thoughtful analysis, the search giant added.

"We can't make a major improvement without affecting rankings for many sites. It has to be that some sites will go up and some will go down. Google depends on the high-quality content created by wonderful websites around the world, and we do have a responsibility to encourage a healthy web ecosystem. Therefore, it is important for high-quality sites to be rewarded, and that's exactly what this change does" Google's engineers wrote at the company's official blog.

Google said that this update does not rely on the feedback the company has received from the Personal Blocklist Chrome extension, which Google launched last week. However, Google compared the Blocklist data it gathered with the sites identified by its algorithm.

The new algorithm has been initially applied to the U.S. only, although Google plans to roll it out elsewhere over time.