In this article we attempt to replicate the hypothesis tested by Rummel and others that external and internal conflict are unrelated. We do this using data for 125 nations for the years 1966-1967. As did Rummel, we use exploratory factor analysis and regression analysis; in addition, we also...

It has often been observed in experimental studies that the reliability of items increases if the same questions are asked of the same respondents more than once. This phenomenon, called the “Socratic effect,†also occurs in nonexperimental, short-wave panel studies. In the first...

Linear-additive age-period cohort models that permit the maximum number of aging effects, period effects, and cohort effects (full cohort models) are underidentified. In this article, some general rules will be given for detecting identified and underidentified parameters in any full cohort...

This article focuses on three main points: (1) Because a short-wave panel study such as the ALLBUS-Retest Study 1984 is suited optimally for reliability estimations, the quality of a larger number of items concerning attitudes about the welfare state and inequality and toward a minority group in...