Utilizing the perspective of finite mixture modeling, this note considers whether a finding of a plausible one-parameter logistic model could be spurious for a population with substantial unobserved heterogeneity. A theoretically and empirically important setting is discussed involving the mixture of two latent classes, with the less restrictive…

The literature on bibliometric indices for assessing scholarly impact, in particular the "h" index (Hirsch, 2005) and its many variants, is extensive, but nevertheless Ruscio and colleagues (this issue) succeed in making a valuable contribution. They have made the effort of collecting publication and citation data for no less than 1,750…

Ruscio and colleagues (Ruscio, Seaman, D'Oriano, Stremlo, & Mahalchik, this issue) have done a great service by systematically comparing indices of scholarly impact. Three aspects of their work are particularly valuable: (1) Their assessment of the proliferating collection of metrics, whose development has become something of a cottage industry,…

In their article Ruscio et al. (Ruscio, Seaman, D'Oriano, Stremlo, & Mahalchik, this issue) present a comparative study of some of the different variants of the "h" index. The study evaluates a total of 22 metrics, including the "h" index and "h"-type indices, as well as other conventional measures. The novelty of their work is to a large extent…

Describing, explaining, and discussing various modern indices of scholarly impact as accomplished by Ruscio, Seaman, D'Oriano, Stremlo, and Mahalchik (this issue) is highly commendable, as such measures get increasingly important in hiring and promotion decisions. The author agrees with almost all points made in the target article, except the…

Definitions of measurement equivalence in terms of invariance can be specified at a very general formal level. Presently, however, only the operationalization of measurement equivalence in terms of factor models is at stake. In this article, the author discusses the proposed alternative definition in terms of idiographic filters in the context of…