What we did was try to expand on the existing literature which documents a correlation between a use of social media and negative mental health outcomes and try to come in with something that can more plausibly establish causation, more plausibly say that social media causes, in fact, negative effects on mental health. When we applied it to our empirical case, we are basically comparing the changes in the mental health of college students in colleges that just received Facebook versus changes in mental health conditions of college students in colleges that did not receive Facebook at the time.