Examines the 80/20 rule that relates to productive sources in a bibliography. Highlights include applications in library acquisition policies, library circulation and weeding policies, science policy studies, information science, and econometrics; formulae of Burrell and of Egghe; probabilistic proofs; geometric distributions; Lotka distribution;…

The precision of the group-based item-response theory (IRT) model applied to school ability estimation is described, assuming use of Bayesian estimation with precision represented by the standard deviation of the posterior distribution. Similarities with and differences between the school-based model and the individual-level IRT are explored. (SLD)

A useful method is proposed for identifying a variable as inconsistent in factor analysis. The procedure, based on the likelihood principle, is illustrated. Statistical properties such as the effect of misspecified hypotheses, the problem of multiple comparisons, and robustness to violation of distributional assumptions are investigated. (SLD)

To assess problems in hypothesis testing and model comparisons based on normed indices caused by latent class models with sparse contingency tables, a simulation was carried out investigating the distributions of the likelihood ratio statistic, the Pearson statistic chi-square, and a new goodness of fit statistic. (SLD)

Describes a study that analyzed transaction logs of users of Excite, an Internet search service. Highlights include data on sessions (changes in queries, number of pages viewed, and relevance feedback), queries (number of search terms and the use of logic and modifiers), and terms (rank/frequency distribution); user characteristics; and failure…

Reports on the development of the Hebrew language translation of the Bath County Computer Attitude Scale among a sample of 339 undergraduate students in Israel. The data support the reliability and validity based on frequency, correlation, reliability, and factor routines analyzed with the SPSS (Statistical Package for the Social Sciences).…

An alternative two-stage least squares (2SLS) estimator of the parameters in LISREL type models is proposed and contrasted with existing estimators. The new 2SLS estimator allows observed and latent variables to originate from nonnormal distributions, is consistent, has a known asymptotic covariance matrix, and can be estimated with standard…

A trilinear chart for understanding the distribution of achievement levels of students' performance in the National Assessment of Educational Progress (NAEP) is described and its use illustrated with data from the 1992 state NAEP mathematics assessment. Trends for all 44 participating jurisdictions are simultaneously displayed. (SLD)

Analyzed data from a session of the General Certificate of Secondary Education (GCSE) mathematics examination to identify items displaying a bi-modal expected score distribution, try to explain the bi-modality, rescore the items to remove under-used middle categories, and determine the effect on test reliability of rescoring the data. Discusses…

A new item parameter replication method is proposed for assessing the statistical significance of the noncompensatory differential item functioning (NCDIF) index associated with the differential functioning of items and tests framework. In this new method, a cutoff score for each item is determined by obtaining a (1-alpha ) percentile rank score…

How do people judge which of 2 risks claims more lives per year? The authors specified 4 candidate mechanisms and tested them against people's judgments in 3 risk environments. Two mechanisms, availability by recall and regressed frequency, conformed best to people's choices. The same mechanisms also accounted well for the mapping accuracy of…

Purpose: This article sheds light on some basic questions about the distribution of educational leadership preparation degree programs among different types of institutions and the distribution of advanced degrees, by type, exploring change over time and the relationship to regional labor market estimates. Method: We used data from five major…

This study was designed to compare the accuracy of three commonly used ability estimation procedures under the graded response model. The three methods, maximum likelihood (ML), expected a posteriori (EAP), and maximum a posteriori (MAP), were compared using a recovery study design for two sample sizes, two underlying ability distributions, and…

An optimization model is presented that allows test assemblers to control the shape of the observed-score distribution on a test for a population with a known ability distribution. An obvious application is for item response theory-based test assembly in programs where observed scores are reported and operational test forms are required to produce…

A simple scheme is proposed for smoothly approximating the ability distribution for relatively long tests, assuming that the item characteristic curves (ICCs) are known or well estimated. The scheme works for a general class of ICCs and is guaranteed to completely recover the theta distribution as the test length increases. The proposed method of…