Problem: In the social sciences, establishing causation is extraordinarily difficult. Often, however, there's an assumption that when two variables appear to together, they are causally related. Take, for instance, the following: In 2017, President Trump signed into law his signature Cuts and Jobs Act. In 2018, the U.S. experienced nearly 3% growth in gross domestic product (GDP). Are the legislation and economic growth causally related? Explain. What must a researcher do to establish causation?