http://www.washingtonpost.com/blogs/the-switch/wp/2018/01/24/facebook-defends-its-simple-2-question-survey-on-the-trustworthiness-of-news-publishers/

The head of Facebook's News Feed defended the company's two-question survey aimed at cutting down on the spread of fake news in a rolling series of tweets this week after critics argued that the survey could be manipulated and would fail to accurately gauge the quality of news outlets.

According to Facebook's Adam Mosseri, Facebook will sample a new set of users each day, and use only those responses  in the company's  evaluations of trustworthiness. It's unclear how many users will be surveyed and what other information will be pulled into the assessment.