Purpose: The purpose of this paper is to give a brief introduction to Second Life, and to provide an outline of how one academic librarian has got involved with using it and reviews the issues that have arisen from a library perspective. Design/methodology/approach: The paper offers a reflection on whether library activities in Second Life are…

Existing research on the Spanish-language translation of the Personality Assessment Inventory (PAI; L. C. Morey, 1991) suggests that the validity scales from the English- and Spanish-language versions may not be equivalent measures. In the current study, 72 bilingual participants completed both the English- and Spanish-language versions of the PAI…

Regressions can be weighted by propensity scores in order to reduce bias. However, weighting is likely to increase random error in the estimates, and to bias the estimated standard errors downward, even when selection mechanisms are well understood. Moreover, in some cases, weighting will increase the bias in estimated causal parameters. If…

Reply to comments on an article "Issues With the SIMPLE Model: Comment on Brown, Neath, and Chater" (2007) by Bennet Murdock on the current authors' original article "A temporal ratio model of memory" by Brown, Neath, and Chater. Does a single mechanism underpin serial and free recall? B. Murdock (2008) argued against the claim, embodied in the…

We examined whether objective feedback would enhance performance when individuals were paid monetary incentives. A two-by-two factorial design was used, with 123 college students assigned to incentive pay without feedback, incentive pay with feedback, fixed pay without feedback, or fixed pay with feedback. Participants attended six sessions and…

In this paper, normal/independent distributions, including but not limited to the multivariate t distribution, the multivariate contaminated distribution, and the multivariate slash distribution, are used to develop a robust Bayesian approach for analyzing structural equation models with complete or missing data. In the context of a nonlinear…

Due to advances in computer and network technology, virtual reality (VR) is no longer just an area of scientific research. It has also become a popular consumer product, as demonstrated by the proliferation of massive multiplayer online role-playing games. Second Life (SL), in particular, has gained popularity among casual users since it became…

Missing data are nearly always a problem in research, and missing values represent a serious threat to the validity of inferences drawn from findings. Increasingly, social science researchers are turning to multiple imputation to handle missing data. Multiple imputation, in which missing values are replaced by values repeatedly drawn from…

A single-subject design was used in 2 experiments about the effects of percentage payback (winnings in proportion to total amount bet) on gambling on a slot-machine simulation in 8 adult humans. In Experiment 1, percentage payback was varied across a wide range of values, and participants were exposed extensively to percentage-payback conditions.…

In the course of screening a form of a medical licensing exam for items that function differentially (DIF) between men and women, the authors used the traditional Mantel-Haenszel (MH) statistic for initial screening and a Bayesian method for deeper analysis. For very easy items, the MH statistic unexpectedly often found DIF where there was none.…

When estimating causal effects from observational data, it is desirable to approximate a randomized experiment as closely as possible. This goal can often be achieved by choosing a subsample from the original control group that matches the treatment group on the distribution of the observed covariates. However, sometimes the original control group…

The examination of measurement invariance in polytomous items is complicated by the possibility that the magnitude and sign of lack of invariance may vary across the steps underlying the set of polytomous response options, a concept referred to as differential step functioning (DSF). This article describes three classes of nonparametric DSF effect…

Equating functions are supposed to be population invariant, meaning that the choice of subpopulation used to compute the equating function should not matter. The extent to which equating functions are population invariant is typically assessed in terms of practical difference criteria that do not account for equating functions' sampling…

Recent work addressing the phenomenon of perceptual simulation offers new and exciting avenues of investigating how to model knowledge representation. From the perspective of language, the simulation approach has given rise to new impetus to work on models of language understanding (e.g., Zwaan, 2004, and references therein), and provides a way of…

There has been a body of emerging research describing students' understanding of complex systems. This research has primarily studied students understanding of complex phenomena in science. However, complex phenomena are also pervasive in everyday life. Children observe and participate in them daily. How do they reason about such ordinary complex…