If standard two-parameter item response functions are employed in the analysis of a test with some newly constructed items, it can be expected that, for some items, the item response function (IRF) will not fit the data well. This lack of fit can also occur when standard IRFs are fitted to personality or psychopathology items. When investigating…

Aggregate-level conditional status metrics (ACSMs) describe the status of a group by referencing current performance to expectations given past scores. This article provides a framework for these metrics, classifying them by aggregation function (mean or median), regression approach (linear mean and nonlinear quantile), and the scale that supports…

The authors performed a Monte Carlo simulation to empirically investigate the robustness and power of 4 methods in testing mean differences for 2 independent groups under conditions in which 2 populations may not demonstrate the same pattern of nonnormality. The approaches considered were the t test, Wilcoxon rank-sum test, Welch-James test with…

Racial and socioeconomic stratification have long governed patterns of residential sorting in the American metropolis. However, recent expansions of school choice policies that allow parents to select schools outside their neighborhood raise questions as to whether this weakening of the neighborhood-school connection might influence the…

Research Findings: Although there has been considerable research on the associations between the qualifications of teachers in center-based settings and preschool-age children's developmental outcomes, very little is known about the relationships between home provider qualifications and the developmental outcomes of toddlers who attend licensed…

Utilizing a web-based simulation Statecraft, we explore the relative influence of ideology (realism and idealism) on student behavior and learning. By placing students into ideologically cohesive groups, we are able to demonstrate the effect of their ideology on the goals they pursue and identify the constraints imposed on the system by the…

This study examines learning gains of college students' performance in critical thinking, reading, writing, and mathematics as assessed by the ETS Proficiency Profile (EPP). In this study, students' college learning gain was estimated by calculating the score differences between their first and last test administrations. Results revealed that (a)…

Propensity score weighting is one of the techniques used in controlling for selection biases in nonexperimental studies. Propensity scores can be used as weights to account for selection assignment differences between treatment and comparison groups. One of the advantages of this approach is that all the individuals in the study can be used for…

Background: "Streptococcus pneumoniae" (SP) pneumonia is often treated empirically as diagnosis is challenging because of the lack of a perfect test. Using BinaxNOW-SP, a urinary antigen test, as an add-on to standard cultures may not only increase diagnostic yield but also increase costs. Objective: To estimate the sensitivity and…

Purpose: Some confounders are nonlinearly associated with dependent variables, but they are often adjusted using a linear term. The purpose of this study was to examine the error of mis-specifying the nonlinear confounding effect. Methods: We carried out a simulation study to investigate the effect of adjusting for a nonlinear confounder in the…

This article assesses how people reason with categories whose features are related in causal cycles. Whereas models based on causal graphical models (CGMs) have enjoyed success modeling category-based judgments as well as a number of other cognitive phenomena, CGMs are only able to represent causal structures that are acyclic. A number of new…

We briefly discuss the philosophical basis of science, causality, and scientific evidence, by introducing the hidden but most fundamental principle of science: the similarity principle. The principle's use in scientific discovery is illustrated with Simpson's paradox and other examples. In discussing the value of null hypothesis statistical…

While interest in Bayesian statistics has been growing in statistics education, the treatment of the topic is still inadequate in both textbooks and the classroom. Because so many fields of study lead to careers that involve a decision-making process requiring an understanding of Bayesian methods, it is becoming increasingly clear that Bayesian…

The activities workers engage in during their personal time are likely to influence whether workers return to work feeling reenergized, refreshed, and fully rested. Two longitudinal studies were conducted to examine the importance of nonwork creative activity during the weekend on workers' state of feeling recovered at work on Monday. Job titles…

Nonnormality of data presents unique challenges for researchers who wish to carry out structural equation modeling. The subsequent SPSS syntax program computes bootstrap-adjusted fit indices (comparative fit index, Tucker-Lewis index, incremental fit index, and root mean square error of approximation) that adjust for nonnormality, along with the…