Why did George Gallup’s 1936 poll predict Franklin D. Roosevelt’s reelection more accurately than the Literary Digest survey?

George Gallup’s 1936 poll successfully predicted Franklin D. Roosevelt’s reelection because he utilized more effective sampling techniques than the Literary Digest survey.12

The Literary Digest incorrectly predicted the election outcome because its sample was fundamentally flawed. It drew respondents from telephone books and automobile registration lists, which disproportionately represented affluent citizens who were more likely to support the Republican candidate, Alfred M. Landon. This created a significant selection bias that failed to reflect the broader American electorate.3

In contrast, Gallup and his contemporaries employed novel methods, such as quota sampling, to create a more accurate "small replica" of the population. By intentionally matching the characteristics of the sample—such as income, education, and residence—to those of the actual population, they were able to account for demographic diversity and achieve a more representative result. This success helped establish the American Institute of Public Opinion as a leader in the field of public opinion research.124