When there exist omitted effects, measurement error, and/or simultaneity in multilevel models, explanatory variables may be correlated with random components, and standard estimation methods do not provide consistent estimates of model parameters. This paper introduces estimators that are consistent under such conditions. By employing generalized…

In many practical situations scaling the data is necessary to solve linear programs. This note explores the relationships in translating the sensitivity analysis between the original and the scaled problems.

Under predetermined conditions on the roots and coefficients, necessary and sufficient conditions relating the coefficients of a given cubic equation x[cubed] + ax[squared] + bx + c = 0 can be established so that the roots possess desired properties. In this note, the condition for one root of a cubic equation to be "the negative reciprocal of…

Choosing mental, written, or calculator procedures is important for children to learn. Children should be encouraged to be flexible and consider alternatives when doing mental calculation. Developing mental skills, symbols and rules, and numbers in context are each considered. (MNS)

A set of three problem-solving programs designed as drills that give practice in mental arithmetic are reviewed. The programs are viewed to have several weaknesses in style, but are noted as worthy of consideration for purchase. The material is designed to motivate students to practice all four basic operations. (MP)

Discusses mental computation and how and when it should be taught. Describes seven properties of mental algorithms. (YP)

Mathematics curriculum documents highlight the need for students to be able to choose from a repertoire of computational tools and strategies, but little direction is given as to how children choose which form of computation to use in any given situation. In this article, the author reports on the classroom implications of research designed to…

Using differentiated instruction in the classroom can be a challenge, especially when teaching mathematics. This book cuts through the difficulties with two powerful and universal strategies that teachers can use across all math content: Open Questions and Parallel Tasks. Specific strategies and examples for grades Kindergarten - 8 are organized…

This study linked nonlinear profile analysis (NPA) of dichotomous responses with an existing family of item response theory models and generalized latent variable models (GLVM). The NPA method offers several benefits over previous internal profile analysis methods: (a) NPA is estimated with maximum likelihood in a GLVM framework rather than…

This research investigates the incidence and wage effects of overskilling for vocational education and training (VET) graduates in Australia between 2001 and 2006. Overskilling is defined as the extent to which workers are able to use their skills and abilities in their current job. The authors compare overskilling with other measures of skill…

This article calls attention to testing as an integral part of teaching mental computation. It begins with an overview of students' performance and is followed by some specific suggestions for testing mental computation skills in the classroom. (Author)

A study of activities in mental computation and in paper and pencil enrichment activities for sixth graders showed that both treatments produced increases in achievement test scores. Examples of both types of activities used are included. (DT)

Two mental algorithms, one for addition and one for subtraction, are described. It is felt such algorithms should be taught explicitly. The usual process taught for paper and pencil is seen to inhibit mental arithmetic, and a need to include mental algorithms in the regular mathematics curriculum is promoted. (MP)

This paper describes how decisions were made on procedures for counting the homeless population for the 1990 census. These topics are covered: (1) reasons the Census Bureau did not specifically label anyone as "homeless" while still including homeless persons in the census; (2) how the lists of sites where homeless persons might be found were…