How children can be guided to see and feel the power of thinking with and about mathematical symbols is discussed. A strategy to help them bridge the gap between manipulative models and symbols is detailed. (MNS)

Qualitative evidence for the operation of partial knowledge is given by two findings. First, performance when second and subsequent choices are made is above the chance level. Second, it is positively related to first choice performance. A number of theories incorporating partial knowledge are compared quantitatively. (Author/LMO)

A method is described for representing quadratic functions by three-dimensional wire models. This enables one to form a simple geometric concept of the location of imaginary zeros. (MNS)

The use of a variety of models to develop number concepts is advocated. Four models are discussed, with illustrations: the cardinal number of a set, Cuisenaire rods, the number line, and the Papy Minicomputer. (MNS)

The purpose of the current study was to investigate the relative performance of the parametric, rank, and normal scores procedures when the classical assumptions were met and under violations of these assumptions. This investigation included the normal scores as well as the rank test. (LMO)

Using manipulative materials and pictures is considered valuable, but the need to use models appropriate for individual children is stressed. Suggestions for using well-structured physical space are given. (MNS)

A questionnaire is designed to allow assessment of a simple additive value function for testing respondent preferences for different types of information used in evaluating police services. Responses are analyzed to determine what types of information different stakeholder groups consider useful. (Author/LMO)

A general approach is proposed for modeling the structure of a r x s contingency table and for drawing marginal inferences about all parameters (e.g., interaction effects) in the model. The main approach is relevant whenever rs minus r minus s plus 1 is greater than or equal to 5. Military aptitude test data is used as illustration. (Author/LMO)

A statistical model is proposed for both contextual analysis and slopes as outcomes analysis. A random coefficient model is investigated in detail. Various estimation models are reviewed and applied to a Dutch school-career example. (Author/LMO)

This article extends both the logic and the statistical procedures used in a recent analysis of Hyde's data on gender differences in cognitive abilities by Rosenthal and Rubin. The logic of a "model fitting" approach to meta-analysis is described. Relevant statistical procedures and goodness-of-fit tests are illustrated. (Author/BS)

An equating design in which two groups of examinees from slightly different populations are administered a different test form with a subset of common items is widely used. This paper presents standard errors and a simulation that verifies the equation for large samples for an equipercentile equating procedure for this design. (Author/BS)

Presents an economic model of the relationship among educational effort, ability, employment qualifications, and productivity. Suggests that occupational competency requirements may encourage applicants to restrict their investments in education to the minimum necessary to obtain certification, rather than striving for competency levels that would…

Two models are presented that can be understood by students who have completed second-year algebra, as well as by calculus students. The predator-prey population model and the arms race model are included, with a computer program given for each. (MNS)

This paper develops and illustrates a latent trait approach to constructing an item bank when responses are scored in several ordered categories. This approach is an extension of the methodology developed by Choppin, Wright and Stone, and Wright and Bell for the construction and maintenance of banks of dichotomously scored items. (Author/PN)

The National Board of Medical Examiners uses the Rasch model to calibrate test items, maintain item banks, equate scores, and monitor the consistency of examiner item response patterns. The model is also being used in the study of patient management problems examinations, standard-setting, and computer-based examinations. (Author/BS)