Meehl's taxometric method was developed to distinguish categorical and continuous constructs. However, taxometric output can be difficult to interpret because expected results for realistic data conditions and differing procedural implementations have not been derived analytically or studied through rigorous simulations. By applying bootstrap…

The range of response options has been shown to influence the answers given in self-report instruments that measure behaviors ranging from television viewing to sexual partners. The current research extends this line of inquiry to 36 quantitative items extracted from a biographical inventory used in personnel selection. A total of 92…

Status quo approaches to teacher evaluation have recently come under increasing criticism. They typically assign most teachers the highest available score, provide minimal feedback for improvement, and have little connection with student achievement growth and the quality of instruction that leads to higher student growth. A more comprehensive…

Confidence intervals (CIs) give information about replication, but many researchers have misconceptions about this information. One problem is that the percentage of future replication means captured by a particular CI varies markedly, depending on where in relation to the population mean that CI falls. The authors investigated the distribution of…

Distinguishing between discrete and continuous latent variable distributions has become increasingly important in numerous domains of behavioral science. Here, the authors explore an information-theoretic approach to latent distribution modeling, in which the ability of latent distribution models to represent statistical information in observed…

Direct provision of public services can alter the balance of resources across income groups. We focus on the issues arising when taking account of the impact of publicly provided education services across the income distribution. We combine OECD information on spending per student in particular levels of the education system with micro data from…

This Digest provides a review and applications of the concepts of normal distribution, standard deviation, effect size, and translation of effect size into percentile gain, the foundations for the understanding of meta analytic results. Meta analysis is a statistical technique that enables the results of a number of studies to be combined to…

Multivariate techniques have been implemented with greater and greater frequency. In order to use multivariate techniques researchers must understand the fundamental assumptions. The purpose of this paper is to evaluate one of the assumptions of multivariate analysis, normality. Overall, normal distributions are unimodal and symmetrical, and they…

The assumption that is most important to the hypothesis testing procedure of multiple linear regression is the assumption that the residuals are normally distributed, but this assumption is not always tenable given the realities of some data sets. When normal distribution of the residuals is not met, an alternative method can be initiated. As an…

Explains two basic approaches to bibliometric models (frequency-size, frequency-rank); cites 28 models; and analyzes three models--Price, Bookstein, and Brookes--by considering their internal properties, interrelationships, and generality. Validity of the generalizations is noted. Appendices include 32 references and list of 28 additional…

Presents table for determining relative rarity of quotient discrepancies on Wechsler Intelligence Scale for Children-Revised (WISC-R) to be used with children at higher Intelligence Quotient levels. Theoretically derived table has been confirmed through empirical observation of WISC-R standardization sample. Suggests table use should reduce…

Discussion of authorship distributions focuses on the results of a numerical study for fractional authorship attribution. Highlights include coauthors; multinomial coefficients; Lotka functions; probability distributions of articles per author; and probability distributions of authors per article. (LRW)

Discusses structural differences between author-publication systems and journal-article systems, i.e., articles can have more than one author. Frequency functions are examined; and a new conceptual explanation of Lotka's Law, based on convolution theory, is proposed. (Contains eight references.) (LRW)

A model for preferential and triadic choice is derived in terms of weighted sums of central F distribution functions. It is a probabilistic generalization of Coombs' (1964) unfolding model from which special cases can be derived easily. This model for binary choice can be easily related to preference ratio judgments. (SLD)

Developed an empirical Bayes enhancement to Mantel-Haenszel (MH) analysis of differential item functioning (DIF) in which it is assumed that the MH statistics are normally distributed and that the prior distribution of underlying DIF parameters is also normal. (Author/SLD)