Australasian Science: Australia's authority on science since 1938

Counting the Opinions

By Peter Bowditch

The same-sex marriage survey repeats the statistical mistakes of most opinion polls.

The full text of this article can be purchased from Informit.

People who might never have heard of George Santayana would still be familiar with the quote: “Those who cannot remember the past are condemned to repeat it”. Australia has been going through a process that repeats mistakes from the past.

The 1936 US presidential election was between the incumbent Democrat Franklin D. Roosevelt and Republican Alf Landon, Governor of Kansas. Roosevelt was partway through implementing his New Deal program, something which was seen by many conservatives as ushering in a form of socialism and anathema to those who saw libertarianism, small government and individual personal freedom as the foundations of US polity.

The magazine The Literary Digest mailed out about 10 million survey forms to subscribers and others, asking them to predict who would win. The 2.3 million replies suggested that Landon would win 370 of the 531 Electoral College votes, and therefore the Presidency. Yet Roosevelt received 500 Electoral College votes and more than 60% of the popular vote.

So how did The Literary Digest get the prediction so wrong? One suggestion was that the subscriber base of the magazine consisted predominantly of conservative voters, so they were the wrong people to ask. The real problem, however, was a combination of this and also that the respondents were a self-selected sample of people motivated enough to fill in a form, put...

The full text of this article can be purchased from Informit.