Surveys facts & stats

Question 1

In 1936, George Gallup correctly predicted an election outcome that a much larger rival poll got wrong. Whose win did he correctly call?

Accepted Answer

Franklin Roosevelt. Gallup used a smaller, more scientific sample to correctly predict Franklin Roosevelt's 1936 re-election, while the giant Literary Digest poll wrongly picked Alf Landon.

Question 2

What sample size do typical U.S. political polls use as a cost/accuracy compromise?

Accepted Answer

500 to 1,000 people. Most political polls settle on 500 to 1,000 respondents, balancing the cost of a larger sample against the accuracy it would add.

Question 3

For a poll of 1,000 people showing about 50% on a question, what is the typical margin of error?

Accepted Answer

about ±3%. A random sample of 1,000 people gives a margin of error around ±3% for a result near 50% — cutting that to ±1% would need about 10,000 respondents.

Question 4

The Likert scale — the common 'strongly disagree to strongly agree' survey format — was invented in what year?

Accepted Answer

1932. Psychologist Rensis Likert introduced his now-ubiquitous rating scale in a 1932 paper, and it remains the most widely used survey response format.

Surveys facts & stats

Going deeper

In 1936, George Gallup correctly predicted an election outcome that a much larger rival poll got wrong. Whose win did he correctly call?

What sample size do typical U.S. political polls use as a cost/accuracy compromise?

Expert level

For a poll of 1,000 people showing about 50% on a question, what is the typical margin of error?

The Likert scale — the common 'strongly disagree to strongly agree' survey format — was invented in what year?