Facebook has released a new tool that the company says will make it easier for users to evaluate news stories and publishers. The changes to Facebook’s News Feed were launched Tuesday for all users in the United States. The social media service says the tool aims to provide “more context” for people to decide for themselves “what to read, trust and share.” The tool is based on research that identified the kinds of information that can be most helpful in deciding whether a news story is credible and trustworthy, Facebook said. It says users should have as much information as possible about publishers to help them recognize accurate news sources. U.S. users can now click a button in News Feed that pulls up a window called “About This Article.” In this window, Facebook provides more information about the news article and publisher.