Science of Politics: Iowa Caucus

The state of Iowa becomes the center of the American political universe every four years when its citizens vote first in a series of presidential primaries and caucuses. But what is behind the fascination with this relatively small constituency?

Prof David Redlawsk, co-author of Why Iowa?, explains how to win the first election of the voting season, which factors play a role in the media coverage of the race, and what the results can tell us about the rest of the campaign cycle.

Produced by the BBC's Franz Strasser.