The Social Science Data Center of the University of Connecticut houses data from hundreds of opinion surveys of the American public, conducted from the mid-1930s up to the present. We have drawn heavily upon these materials, particularly on some one hundred and fifty American Institute for Public Opinion (AIPO) surveys, commonly known as the Gallup Polls. 1
There are several reasons for our reliance upon the AIPO studies. They constitute the longest continuous stream of survey information on the American public— covering the entire span since the New Deal. In overall quality and consistency, the Gallup Polls deserve very high marks. So numerous are these surveys, moreover, with more than twenty conducted each year, that it is possible to "check in" on the electorate with a high measure of regularity. It is also possible to combine several AIPO surveys in a limited time span—a strategy used by George Gallup in many of his own analyses, and by a number of other investigators—to create a national sample with very large numbers of respondents among strategic subgroups, and to minimize sample bias. Routinely we pooled four AIPO surveys conducted just before and after a presidential or congressional election.
For the years since 1952, we also relied upon the University of Michigan biennial election studies. 2 Our debt is greater than the reader might suspect, since relatively little of the Michigan data actually appears in the text. We____________________