The importance of accuracy may be illustrated through the example of the Literary Digest Roosevelt-Landon presidential election poll. After correctly predicting the victories of Warren Harding in 1920, Calvin Coolidge in 1924, Herbert Hoover in 1929, and Franklin Roosevelt in 1932, the Literary Digest had established itself as a well-known and well-respected publication. One reason for their previous successes was the use of a very large sample population.
The Literary Digest
The Literary Digest conducted the first national poll.
In 1936, the Digest conducted their presidential poll with 2.3 million voters, a huge sample size. However, the sample turned out to be an inaccurate representation of the general population as those polled were generally more affluent Americans who tended to have Republican sympathies. The Literary Digest was ignorant of this new bias. The week before Election Day, it reported that Alf Landon was far more popular than Roosevelt. At the same time, George Gallup conducted a far smaller, but more scientifically based survey, in which he polled a more demographically representative sample. Gallup correctly predicted Roosevelt's landslide victory. The Literary Digest lost its reputation for accuracy and the trust of the readers and soon went out of business.
Maintaining Polling Accuracy
Relevance of the survey information, quality of the data, and overcoming personal bias are integral to polling accuracy.
When releasing information, data and official statistics should be relevant to the needs of users as well as both public and private sector decision makers. The quality of results must be assessed prior to release. If errors in the results occur before or after the data revision, they should be corrected and users should be informed as quickly as possible. Finally, when social scientists speak of "good research," the focus is on how the research is done–whether the research is methodologically sound–rather than on whether the results of the research are consistent with personal biases or preconceptions.
Glenn Firebaugh summarizes the principles for good research in his book Seven Rules for Social Research. He states that "there should be the possibility of surprise in social research. " In other words, it is imperative that the researchers look past their preconceived notions or desires to conduct a study that reflects whatever the reality may be. Additionally, good research will "look for differences that make a difference" and "build in reality checks. " Researchers are also advised to replicate their polls, that is, "to see if identical analyses yield similar results for different samples of people. " The next two rules urge researchers to "compare like with like" and to "study change;" these two rules are especially important when researchers want to estimate the effect of one variable on another. The final rule, "let method be the servant, not the master," reminds researchers that methods are the means, not the end, of social research; it is critical from the outset to fit the research design to the research issue, rather than the other way around.