Then, in 1936, its survey of 2.3 million voters suggested that Alf Landon would win the presidential election, but Roosevelt was instead re-elected by a landslide. The error was mainly caused by participation bias; those who favored Landon were more enthusiastic about participating in the poll. Furthermore, the survey over-sampled more affluent Americans who tended to have Republican sympathies. At the same time, George Gallup conducted a far smaller (but more scientifically based) survey, in which he polled a demographically representative sample. The Gallup organization correctly predicted Roosevelt's landslide victory. "The Literary Digest" soon went out of business, while polling started to take off.