917 4 1936 Literary Digest Poll From Chapter 1 in the book: Example 1.4.4: Bias The 1936 Literary Digest Poll. The Literary Digest was a magazine that was founded in 1890. Starting with the 1916 U.S. presidential election, the magazine had predicted the winner of each election. In 1936, the Literary Digest predicted that Alfred Landon would win the election in a landslide over Franklin Delano Roosevelt with fifty-seven percent of the popular vote. The process for predicting the winner was that the magazine sent out ten million mock ballots to its subscribers and names of people who had automobiles and telephones. Two million mock ballots were sent back. In reality, Roosevelt won the election with 62% of the popular vote. (\"Case Study 1: The 1936 Literary Digest Poll,\" n.d.) A side note is that while the Literary Digest was publishing its prediction, a man by the name of George Gallup also conducted a poll to predict the winner of the election. Gallup only polled about fifty thousand voters using random sampling techniques, yet his prediction was that Roosevelt would win the election. His polling techniques were shown to be the most accurate method and have been used to the present-day. Selection Bias: Because of the people whom the Literary Digest polled, they created something called a selection bias. The poll asked ten million people who owned cars, had telephones, and subscribed to the magazine. Today, you would probably think that this group of people would be representative of the entire U.S. However, in 1936 the country was amid the Great Depression. So the people polled were mostly in the upper middle to upper class. They did not represent the entire country. It did not matter that the sample was very large. The most important part of a sample is that it is representative of the entire population. If the sample is not, then the results could be wrong, as demonstrated in this case. It is important to collect data so that it has the best chance of representing the entire population. Nonresponse Bias: When looking at the number of ballots returned, two million appears to be a very large number. However, ten million ballots were sent out. So that means that only about one-fifth of all the ballots were returned. This is known as a nonresponse bias. The only people who probably took the time to fill out and return the ballot were those who felt strongly about the issue. So, when you send out a survey, you must pay attention to what percentage of surveys are actually returned. If possible, it is better to conduct the survey in person or over the telephone or internet. Most credible polls conducted today, such as Gallup, are conducted either in person or over the telephone. Do be careful though, just because a polling group conducts the poll in person or on the telephone does not mean that it is necessarily credible. e Discuss the biases presented in the article and e Find or recall any bias in polls that you have seen presented on TV, print, or radio recently