The study is designed to demonstrate and test the utility of the proposed two-stage matching method compared to other analytic methods traditionally employed for multisite observational studies. More specifically, the study addresses the following research questions: (1) How do different specifications of the matching method influence covariate…

The purpose of this study was to examine factors that may or may not contribute to the adoption of the innovation of virtual worlds by librarians. Using Everett Rogers' Diffusion Theory as a framework, the study sought to identify librarians with avatars (computer simulated representations of themselves) in the virtual world of Second Life,…

Propensity score matching is a relatively new technique used in observational studies to approximate data that have been randomly assigned to treatment. This technique assimilates the values of several covariates into a single propensity score that is used as a matching variable to create similar groups. This dissertation comprises two separate…

In this article, we present a Bayesian spatial factor analysis model. We extend previous work on confirmatory factor analysis by including geographically distributed latent variables and accounting for heterogeneity and spatial autocorrelation. The simulation study shows excellent recovery of the model parameters and demonstrates the consequences…

This article is based on a case study that follows the trajectory of a technological device aimed at environmental education from the engineering laboratory in which it was designed into the contexts in which it is used. "Greendrive" is a driving simulator that accurately reproduces the performance of a vehicle in terms of fuel…

We seek to illustrate Fano interference in a classical coupled oscillator by using classical analogues of the atom-laser interaction. We present an analogy between the dressed state picture of coherent atom-laser interaction and a classical coupled oscillator. The Autler-Townes splitting due to the atom-laser interaction is analogous to the…

The present studies examined whether implied tactile properties during language comprehension influence subsequent direct tactile perception, and the specificity of any such effects. Participants read sentences that implicitly conveyed information regarding tactile properties (e.g., "Grace tried on a pair of thick corduroy pants while…

Serving as Rachlin's teaching assistant for his graduate course on animal learning in 1973 determined the direction of the author's career, which has been to build computer models and robots based mostly on the equations from that course and related ones. These artificial beings behave and learn very much like animals, and creating them forces a…

Recent simulation research has demonstrated that using simple raw score to operationalize a latent construct can result in inflated Type I error rates for the interaction term of a moderated statistical model when the interaction (or lack thereof) is proposed at the latent variable level. Rescaling the scores using an appropriate item response…

This study extends the multilevel measurement model to handle testlet-based dependencies. A flexible two-level testlet response model (the MMMT-2 model) for dichotomous items is introduced that permits assessment of differential testlet functioning (DTLF). A distinction is made between this study's conceptualization of DTLF and that of…

This article introduces procedures for the computation and asymptotic statistical inference for classification consistency and accuracy indices specifically designed for cognitive diagnostic assessments. The new classification indices can be used as important indicators of the reliability and validity of classification results produced by…

Previous assessments of the reliability of test scores for testlet-composed tests have indicated that item-based estimation methods overestimate reliability. This study was designed to address issues related to the extent to which item-based estimation methods overestimate the reliability of test scores composed of testlets and to compare several…

Latent class regression models relate covariates and latent constructs such as psychiatric disorders. Though full maximum likelihood estimation is available, estimation is often in three steps: (i) a latent class model is fitted without covariates; (ii) latent class scores are predicted; and (iii) the scores are regressed on covariates. We propose…

This paper compares three methods of item calibration--concurrent calibration, separate calibration with linking, and fixed item parameter calibration--that are frequently used for linking item parameters to a base scale. Concurrent and separate calibrations were implemented using BILOG-MG. The Stocking and Lord in "Appl Psychol Measure"…

Interference and diffraction of light are elementary topics in optics. The aim of the work presented here is to develop an accurate and cheap optical-system simulation software that provides a virtual laboratory for studying the effects of propagation in both time and space for the near- and far-field regions. In laboratory sessions, this software…