1. Designing Social Inquiry week 4 I36005 Soohyung Ahn Case Study 1936 PRESIDENTIAL ELECTION : Roosevelt VS Landon

2. Question? In 1936, FDR, completing his first term of office as president of the US, was running against the Republican candidate, Alf Landon of Kansas. The Literary Digest magazine, in a poll consisting of about 2.4 million individuals, the largest in history, predicted a victory for Landon by 57 percent to 43 percent. Despite this decisive prediction, Roosevelt won the election by a huge landslide – 62 percent to 38 percent. Why do you think Literary Digest failed so dramatically?

3. Contents 1.Background situation 2.The sampling frame used by The Literary Digest 3.Why did this magazine fail to predict? 4.George Gallup’s prediction 5.Conclusion

4. Background In 1936, presidential election : Roosevelt vs. Landon The Literary Digest conducted every presidential election poll from 1916 to 1938.The Literary Digest conducted every presidential election poll from 1916 to 1938. Sample size: 2.4 million out of 10 million. They predicted Landon would win by 57% Election result: It was a landslide for Roosevelt by 62%

5. Why did The Literary Digest have great success in its prediction accuracy prior to 1936? (The sampling frame used by The Literary Digest) It was a famous and popular magazine that successfully predicted the outcome of the presidential election for many years. It used the unscientific straw poll to gauge public opinion and to predict the popular vote. It also used national straw polls in 1920, 1924, 1928 and 1932, and it guessed the winner of each presidential election. “Uncannily accurate” Background (cont’d)

7. Actual result of Election

8. The Literary Digest Poll was biased! Selection bias - The owners of autos and telephones - Lists of magazine subscribers (wealthy people) - Automobile and telephone lists were not representative samples - Roosevelt’s supporters were excluded (the poor) Timing - The ballots were mailed in early September. (the returns were published each week from 6 September to 31 October.) - The Great Depression Nonresponse Bias - Low response rate (2.4 million out of 10 million.) - Do Republicans live nearer mail-boxes than Democrats?

11. A Landmark in Research History The Literary Digest Poll It predicted Landon as next president. The Literary Digest was out of business the following year. Straw polls started in 1824. Straw poll The Gallup Poll George Gallup founded the American Institute of Public Opinion in 1935. It predicted Roosevelt. Gallup used a random poll sample of 50,000 people. He said: Literary Digest would get it all wrong, despite the Digest’s decent track record in previous polls. Random sampling

12. Conclusion Sample size is not a critical issue! It is important to reduce sample bias! Watch out the nonsystematic elements, tend to overwhelm or distort the systematic element.