What does corroborating sources allow a political scientist to do?

It helps them determine whether an assertion made by one source is likely to be true.

FOR FARTHER EXPLANATION

Corroboration is the skill of comparing multiple sources regarding an event to find the most consistent and valid version of the event.

Political scientists would use corroboration to determine political results, polling, campaign progress, as well as bill development. A study on the passage of the Affordable Care Act for example would pull together versions of the bill as well as party opinions on the bill. In writing an assessment on the bill, the political scientists would look at all of the information and come to a conclusion.

roosevelt essentially took the opposite approach as hoover in taking on the great depression. herbert hoover thought that america and its economy could naturally recover from the depression in due course, so he adamantly restrained the federal government from intervening on behalf of the people affected. on the other hand, roosevelt dramatically increased employment by expanding the federal government and establishing agencies that would aid in relieving some of the country's worst problems.