Assessing the Validity of the Postmaterialism Index

Abstract

Inglehart's postmaterialism thesis describes an individual-level process of value change. Little attention has been devoted to validating the responses to his postmaterialist-materialist index. The aggregate-level distributions may appear to reflect a postmaterialist-materialist dimension, even if at the individual level responses on the questions making up the index are random. The logic of the survey questions used for the index defines a baseline against which the actual distribution of responses can be compared. Using such a standard, we find that individual responses are not constrained by an underlying value dimension, in the sense that the observed patterns of responses increasingly do not differ from what one would expect by chance. Furthermore, as one would expect for a random variable, index scores are virtually unexplainable as a dependent variable, and they cannot be used to predict support for various political and social issues, said to flow from attitudes measured by the index.