Analysis of the modernity scale: An Item Response Theory Approach

This article introduces item response theory as a method to test and improve the cross-cultural scalar equivalence of a psychological measurement instrument. A comparison of American Hispanics and Mainstream Americans on the dimension of modernity is also reported. The 25-item Overall Modernity Scale (Inkeles & Smith, 1974) was administered to 432 Hispanic and Mainstream navy recruits. Consistent with previous research, the scale was found to have a single dominant dimension and moderate reliability. Analyses based on item response theory indicted that there was no item bias against either of the two ethnic groups. No difference was found between the mean level of modernity for the Hispanic and Mainstream subjects. Explanations of the lack of cross cultural differences are offered. Issues related to cross-cultural comparisons and the statistical-substantial meanings of item bias are also discussed.