Bare bones,or a rich feast? Taking care with context in a data rich world

Providing a rich context has become a sine qua non of principled teaching of applied statistical thinking. With increasing opportunities to access secondary data, there should be increasing opportunity to work with rich context. We review the contextual information provided in 41 data sets suitable for introductory tertiary statistics teaching, available in the R “datasets” package, and investigate the source information for four data sets. We find failure to describe and retain important contextual information, including aspects that raise questions about the credibility of the data for statistical inference. The sanitization of data reduces the opportunities for learning meaningful lessons in statistical thinking and the real-world application of statistics. We advocate for teachers and users of such data to be curious about the provenance and context, and for the curators and distributors to examine, where possible, the primary sources, to accurately preserve the context and optimize pedagogical opportunities.     

Is it wrong to play violent video games?

Many people have a strong intuition that there is something morallyobjectionable about playing violent video games, particularly withincreases in the number of people who are playing them and the games'alleged contribution to some highly publicized crimes. In this paper,I use the framework of utilitarian, deontological, and virtue ethicaltheories to analyze the possibility that there might be some philosophicalfoundation for these intuitions. I raise the broader question of whetheror not participating in authentic simulations of immoral acts in generalis wrong. I argue that neither the utilitarian, nor the Kantian hassubstantial objections to violent game playing, although they offersome important insights into playing games in general and what it ismorally to be a ``good sport.' The Aristotelian, however, has a plausibleand intuitive way to protest participation in authentic simulations ofviolent acts in terms of character: engaging in simulated immoral actserodes one's character and makes it more difficult for one to live afulfilled eudaimonic life.     

Estimation of Item Response Theory Parameters in the Presence of Missing Data

Missing data are a common problem in a variety of measurement settings, including responses to items on both cognitive and affective assessments. Researchers have shown that such missing data may create problems in the estimation of item difficulty parameters in the Item Response Theory (IRT) context, particularly if they are ignored. At the same time, a number of data imputation methods have been developed outside of the IRT framework and been shown to be effective tools for dealing with missing data. The current study takes several of these methods that have been found to be useful in other contexts and investigates their performance with IRT data that contain missing values. Through a simulation study, it is shown that these methods exhibit varying degrees of effectiveness in terms of imputing data that in turn produce accurate sample estimates of item difficulty and discrimination parameters.     

Individual Differences in the Stability and Change of Childhood Depression: A Growth Mixture Model With Structured Residuals

Studies of developmental trajectories of depression are important for understanding depression etiology. Existing studies have been limited by short time frames and no studies have explored a key factor: differential patterns of responding to life events. This article introduces a novel analytic technique, growth mixture modeling with structured residuals, to examine the course of youth depression in a large, prospective cohort (N = 11,641, ages 4–16.5, 96% White). Age-specific critical points were identified at ages 8 and 13 where depression symptoms spiked for a minority of children. Most depression risk was due to dynamic responses to environmental events, drawn not from a small pool of persistently depressed children, but a larger pool of children who varied across higher and lower symptom levels.     

Comparison of NOHARM and DETECT in Item Cluster Recovery: Counting Dimensions and Allocating Items

This study examines the performance of a new method for assessing and characterizing dimensionality in test data using the NOHARM model, and comparing it with DETECT. Dimensionality assessment is carried out using two goodness-of-fit statistics that are compared to reference χ² distributions. A Monte Carlo study is used with item parameters based on a statewide basic skills assessment and the SAT. Other factors that are varied include the correlation among the latent traits, the number of items, the number of subjects, skewness of the latent traits, and the presence or absence of guessing. The performance of the two procedures is judged by the accuracy in determining the number of underlying dimensions, and the degree to which items are correctly clustered together. Results indicate that the new, NOHARM-based method appears to perform comparably to DETECT in terms of simultaneously finding the correct number of dimensions and clustering items correctly. NOHARM is generally better able to determine the number of underlying dimensions, but less able to group items together, than DETECT. When errors in item cluster assignment are made, DETECT is more likely to incorrectly separate items while NOHARM more often incorrectly groups them together.     

Validity Evidence of an Electronic Portfolio for Preservice Teachers

This study applied Messick's unified, multifaceted concept of construct validity to an electronic portfolio system used in a teacher education program. The subjects included 128 preservice teachers who recently completed their final portfolio reviews and student teaching experiences. Four of Messick's six facets of validity were investigated for the portfolio in this study, along with a discussion of the remaining facets examined in two previous studies. The evidence provided support for the substantive and generalizability aspects of validity, and limited support for the content, structural, external, and consequential aspects of validity. It was suggested that the electronic portfolio may be used as one requirement for certification purposes, but may not be valid for the purpose of assessing teacher competencies .     

A Twin and Adoption Study of Reading Achievement: Exploration of Shared-Environmental and Gene-Environment-Interaction Effects

Existing behavior-genetic research implicates substantial influence of heredity and modest influence of shared environment on reading achievement and reading disability. Applying DeFries-Fulker analysis to a combined sample of twins and adoptees (N = 4,886, including 266 reading-disabled probands), the present study replicates prior findings of considerable heritability for both reading achievement and reading disability. A simple biometric model adequately described parent and offspring data (combined N = 9,430 parents and offspring) across differing types of families present in the sample Analyses yielded a high heritability estimate (around 0.70) and a negligible shared-environmentality estimate for both reading achievement and reading disability. No evidence of gene × environment interaction was found for parental reading ability and parental educational attainment, the two moderators analyzed.