A general latent variable model allows for maximum likelihood estimation with missing data. LISREL and LISCOMP programs may be used to carry out this estimation. Simulated data were generated. The proposed Full, Quasi-Likelihood estimator was found to be superior to listwise present quasi-likelihood and pairwise present approaches. (Author/GDC)

The use of semiparametric models may require incorporating additional functions which do not vary across distributions and may require expressing the models in terms of the joint distribution of response class and response time. (Author/LMO)

A common functional relationship among Lotka's law, Bradford's law, and Zipf's law is derived. The proof takes explicit account of the sequences of observed values of the variables by means of an index. This approach results in a more realistic and precise formulation of each law. (Author/EM)

The derivation of a general retrieval effectiveness measure is investigated. Inconsistencies in the definition of relative importance are resolved, and it is shown that the influence of the assigned weight on the effectiveness measure can produce counterintuitive results. An alternative effectiveness measure provided by the Marczewski-Steinhaus…

A description of a Mokken test program to test the robustness of nonparametric Stochastic scales is presented. For each sample and the whole population, different scale statistics (both on scale and on item level) are computed recursively. A statistic T is presented for testing the robustness of the scales in the samples. (Author)

Correct simple formulas are provided for the value of phi needed to use the commonly available Pearson and Hartley power charts in determining the power of hypothesis tests involving simple degree-of-freedom comparisons in the fixed effects analysis of variance. (LMO)

Proposes an alternative methodology for handling queries with weighted search terms or search criteria in a fuzzy environment as a means of improving the performance of information retrieval systems. (EM)

This study formulates a property of a quantification method, the principle of equivalent partitioning. When used with Guttman's principle of internal consistency, the combination allows the analysis of correlational data in terms of the variate(s) chosen by the investigator. Applications to multiple-choice, rank-order, and paired comparison data…

A general class of differentiation indices is introduced for profiles of scores. Their ordinal properties and an application to Holland's classification system are examined. Comparison with other suggested indices is performed both theoretically and empirically. (Author)

The extension of regression estimation and poststratification to factor analysis is considered. These methods may be used either to improve the efficiency of estimation or to adjust for the effects of nonrandom selection. The estimation procedure may be formulated in a LISTREL framework. (Author/LMO)

Under the assumption of normalcy, a formula is derived for the reliability of the maximum score. It is shown that the maximum score is more reliable than each of the single observations but less reliable than their composite score. (Author/LMO)

Empirical data from a farm-level survey of 1,548 small farmers in Guatemala show that there appears to be a threshold effect and that four or more years of education are needed to have a measurable impact on farm productivity. Appended are 13 references. (MLF)

A sample of 328 freshman economics students is disaggregated by the students' gender, previous knowledge of economics, attitudes toward economics, and innate abilities. Results show that students learn more economics if they take microeconomics before macroeconomics. Appended are 14 references. (MLF)

Empirical estimates of production frontiers and average production functions performed for selected public elementary school districts in California support the hypothesis of an optimal school size model. Some policy implications of the results are briefly analyzed. Appended are 16 references. (MLF)

On the occasion of Psychometrika's fiftieth anniversary, the past twenty-five years' developments in mental test theory are reviewed. Psychometrika articles treating topics in test theory are listed in a bibliography. (Author/LMO)