This paper provides a concise summary of 10 years of research into defining appropriate statistical models for estimating school and teacher effect on student learning and other important educational outcomes. It discusses criteria for judging models and presents the formulae for the two-stage, two-level student-school hierarchical linear modeling…

Test data generated according to two different multidimensional item response theory (IRT) models were compared at both the item response level and the test score level to determine whether measurable differences between the models could be detected when the data sets were constrained to be equivalent in terms of item "p"-values. The…

Analysis of covariance (ANCOVA) is a data analysis method that is often used to control extraneous sources of variation in non-equivalent group designs. It is commonly believed that as long as the covariate is highly correlated with the dependent variable there is nothing to lose in using ANCOVA, even in non-randomized studies. This paper examines…

Discusses how to check the accuracy of different enrollment projection methods for different educational systems. (Author)

A Bayesian procedure is given for estimation in unrestricted common factor analysis. A choice of the form of the prior distribution is justified. The procedure achieves its objective of avoiding inadmissible estimates of unique variances, and is reasonably insensitive to certain variations in the shape of the prior distribution. (Author/BJG)

Forecasting techniques developed by government and industry are being applied to various library statistics. These techniques are explained and examples of their use discussed. (Author)

The computation of the cost of various pay proposals may be reduced to a series of mathematical formulas that may then be utilized in conjunction with an electronic digital computer to quickly and accurately determine the maximum salaries payable with a given amount of funds. (Author)

A model for population growth is described. (SD)

Presents trend projection models that address four problems--dramatic growth, modest growth, gradual decline, and precipitous decline. Each model approximates a linear trend over short time intervals. The models employ very elementary mathematics to produce forecasts of high accuracy. (Author/IRT)

A probabilistic model of keyword indexing is outlined, and some of the consequences of the model are examined. An algorithm defining a measure of indexability is developed--a measure intended to reflect the relative significance of words in documents. (Author)

A new technique, known as discrimination value analysis, ranks the text words in accordance with how well they are able to discriminate the documents of a collection from each other. (Author/PF)

Although analysis of covariance (ANCOVA) is used fairly infrequently in published research, the method is used much more frequently in dissertations and in evaluation research. This paper reviews the assumptions that must be met for ANCOVA to yield useful results, and argues that ANCOVA will yield distorted and inaccurate results when these…

Two-stage sampling procedures for comparing two population means when variances are heterogeneous have been developed by D. G. Chapman (1950) and B. K. Ghosh (1975). Both procedures assume sampling from populations that are normally distributed. The present study reports on the effect that sampling from non-normal distributions has on Type I error…

Modeling the population in survey sampling problems continues to be controversial. An important reason is that the likelihood principle makes it somewhat necessary to model the population. Estimating the population total in two-stage survey sampling is considered, making use of a "superpopulation" model. The problem is then really one of…

An exploratory study of the value of ridge regression for interactive models is reported. Assuming that the linear terms in a simple interactive model are centered to eliminate non-essential multicollinearity, a variety of common models, representing both ordinal and disordinal interactions, are shown to have "orientations" that are…