Getting Entangled in the Nomological Net

Abstract

Psychological research relies heavily on tests and questionnaires to measure constructs and traits. Thus, tests and questionnaires are not only in high demand, but are constantly being developed anew. Likewise, researchers have suggested many new traits or constructs. Such suggestions then cause a wave of test and questionnaire development. This investment of time and research resources is necessary to ensure high-quality measurement tools that can be trusted by other researchers and practitioners as well to assess the intended trait or construct. For this reason, journals such as the European Journal of Psychological Assessment publish studies evaluating the psychometric properties of such new measurement tools. Typically, such evaluation studies include some estimate of reliability (Schweizer, 2011) and concentrate on demonstrating the validity of the score derived from the new measure. A look at the history of this journal reveals that the number of publications that apply some form of factor analysis has risen from around 28% in the 1990s to 40% since the year 2000 (Alonso-Arbiol & van de Vijver, 2010). From this one can assume that the factorial validity of the published measurement tools has been a central theme of published research. Factorial validity is of course an extremely important issue and provides information necessary to many scoring procedures. Since it is trait scores (in their various forms) which are most commonly used in applied studies, factorial validity should not be neglected. However, while a newly devised measurement tool may demonstrate factorial validity and produce reliable test scores, its utility in the field is far from assured. Construct validity-related evidence is still necessary to ensure that the new measure truly captures the trait it was intended to capture. Campbell and Fiske (1959) asserted this as follows: