Use of the Mantel-Haenszel procedure as a test for differential item functioning under the Rasch model of item-response theory is examined. Results of the procedure cannot be generalized to the class of items for which item-response functions are monotonic and local independence holds. (TJH)

Recently, C. E. McCulloch (1987) suggested a modification of the Morgan-Pitman test for comparing the variances of two dependent groups. This paper demonstrates that there are situations where the procedure is not robust. A subsample approach, similar to the Box-Scheffe test, and the Sandvik-Olsson procedure are also assessed. (TJH)

Discusses the interdependencies between parameter estimation and properties of probabilistic models, such as dependency assumptions, binary vs. nonbinary features, and estimation sample selection. An optimum estimation for binary features applicable to information retrieval is defined, a method for computing this estimation using empirical data is…

Argues that a major difficulty in using Lotka's law in information science arises from the misuse of goodness of fit tests in parameter estimation. Three approaches for studying Lotka's law are presented: an index approach, a time series approach, and a generating mechanism incorporating these two influential variables to derive an equilibrium…

Two coefficients ("H" and "C") for evaluating the homogeneity or congruence of a set of ratings or scores are described. Statistical tests of the significance of these indexes are presented, along with a description of a computer program (CHOPRO) for determining values of "C" and "H" and associated…

The robustness of the likelihood ratio difference statistic to the violation of a regularity condition when used to assess differences in fit provided by pairs of latent class models was investigated. Recommendations are made regarding the use of the statistic under violation of the regularity condition. (SLD)

Two observed-score methods that assume equally reliable congeneric tests were compared for the external anchor test equating model. Each derivation was compared to existing test equating methods based on different assumptions. Using samples of Australian secondary school students (N=about 6,000), the methods were compared empirically with existing…

Discusses the master equation of a stochastic model in chemical process systems. Presents a solution technique known as the System Size Expansion. (YP)

In this analysis of 1,815 arbitration cases in British Columbia in 1982-85, bias is identified in the bivariate estimates of the probability of management wins by industry and issue. Bivariate estimate errors in these cases can result from failure of estimates to adjust for the effects of omitted variables. (TJH)

Multivariate and univariate analysis of variance methods (MANOVA and ANOVA, respectively) are compared for their relative value in educational research. The favoritism shown multivariate techniques is questioned. Criteria for the selection of the appropriate technique are outlined. The relationships among research hypotheses, statistical…

The internal correlation--a measure of dependency in a set of variables--is discussed and generalized. Applications of the internal correlation coefficient and its generalizations are given for several data-analytic situations. The internal correlation is illustrated and the concept is expanded to a series of additional indices. (TJH)

Use of internal correlation for statistical analysis--proposed by G. W. Joe and J. L. Mendoza (1989)--is discussed. Focus is on the "content" question (what this application can do with the information that statistics contain) and the "eloquence" question (the advantages of this means of encoding information over other means). (TJH)

Discusses the effect of including relevance data on the calculation of term discrimination values in bibliographic databases. Algorithms that calculate the ability of index terms to discriminate between relevant and non-relevant documents are described and tested. The results are discussed in terms of the relationship between term frequency and…

Multivariate distributions are studied in which all bivariate regressions can be linearized by separate transformation of each of the variables. A two-stage procedure, first scaling the variables optimally and then fitting a simultaneous equations model, is studied in detail. (SLD)

Testing the fit of the Rasch model is examined. Tests proposed are based on the comparison of expected and observed frequencies. Conditional maximum likelihood estimates (MLEs) and marginal MLEs are compared. A statistical testing procedure is proposed that is a diagnostic tool for identifying violations of the Rasch model. (SLD)