The problem of comparing proportions when some data are missing is investigated, and determination is made of what statistical techniques are appropriate under each of several probability models describing the observations likely to be missing. Monte Carlo methods were used to investigate the properties of standard estimators under each of the…

Using the assumption of randomly parallel tests and concepts from generalizability theory, three signal/noise ratios for domain-referenced tests are developed, discussed, and compared. The three ratios have the same noise but different signals depending upon the kind of decision to be made as a result of measurement. (Author/JKS)

The Progress in International Reading Literacy Study (PIRLS) is a large international comparative study of the reading literacy of young students. The student population for the U.S. 2001 PIRLS (hereafter simply referred to as PIRLS) was the set of all fourth-graders in the United States, corresponding to the grade in which the highest proportion…

Study compares the Rasch and the Guttman models of measurement and thus adds to the description of the characteristics of Rasch's logistic model. Such knowledge is of importance in making decisions as to which model and which statistics should be used in evaluations of tests. (Author/CB)

Two methods of analyzing nonorthogonal (uneven cell sizes) cross-classified data sets are compared. The methods are direct standardization and the general linear model. The authors illustrate when direct standardization may be a desirable method of analysis. (JKS)

A polychotomous nominal response model-based computerized adaptive test (CAT) was simulated using data from 1,093 University of Texas students. The ability estimation of this model and its overall performance were compared with those of a dichotomous three-parameter logistic model-based CAT. Advantages and drawbacks of nominal response CAT are…

Reviews three citation-based measures for the study of journal status--influence weight, importance index, and measure of standing--to provide more convenient access to their computation. A subset of nine library and information science journals is used to illustrate simple computational procedures using the SAS statistical software package. (18…

Common approaches to examining the relationship between multitrait-multimethod (MTMM) data and variables outside the MTMM data are compared: averaging various means of each trait and estimating LISREL computer program models, and estimating only relationships between MTMM traits and the outside variables. Problems of correlational bias are…

Analyzes the properties of genetic sequences that cause the failure of classical algorithms used for data compression. A lossless algorithm, which compresses the information contained in DNA and RNA sequences by detecting regularities such as palindromes, is presented. This algorithm combines substitutional and statistical methods and appears to…

The reliability of residual scores created in the analysis of covariance in pretest-posttest designs, adjusted for a singe covariate, is compared with that of simple difference scores as relevant parameters vary. Little gain in reliability is created by analysis of covariance, which also suffers from reliability problems. (SLD)

Modifications are proposed to the recently developed method of comparing one-step M-estimators of location corresponding to two independent groups that provides good control over the probability of Type I error even for unequal sample size, unequal variances, and different shaped distributions. Simulation results reveal cautions required. (SLD)

Applies multilevel models of cost-effectiveness to numerous types of (British) institutions providing courses of instruction in the General Certificate of Education at Advanced Level. Different impressions may be gained about an institution's relative effectiveness when cost considerations are combined with outcome measures. Data evaluation needs…

Two experiments tested a neo-Piagetian model of verbal short-term memory, comparing it with the articulatory loop model. Findings indicated that the proposed model accounted for effects of M capacity, word length, and presentation modality on short-term memory. The model's fit to the data was acceptable, and parameter estimates were consistent…

In three studies, we investigated to what extent a geometrical representation in a psychological space succeeds in predicting typicality in animal, natural food and artifact concepts and whether contrast categories contribute to the prediction. In Study 1, we compared the predictive value of a family resemblance-based prototype model with a…

An overview is given of the available statistical theory and software for analyzing hierarchically nested data. Programs are evaluated, and general techniques are proposed to analyze data from several domains. This research is part of a larger project to evaluate elementary education in the Netherlands. The models discussed are the random…