The purpose of the study was to examine differences in early numerical competencies, as well as subtraction skill, as a function of children's mathematics difficulty (MD) status: computational difficulty (CD), word problem-solving difficulty (PD), concurrent difficulty (CDPD), or neither difficulty (i.e., typically developing; TYP). Based on…

The combined seventh-grade and eighth-grade class began each day with a mathematical reasoning question as a warm-up activity. One day's question was: Is the product of two odd numbers always an odd number? The students took sides on the issue, and the exercise ended in frustration. Reflecting on the frustration caused by this warm-up activity,…

As is the case for any statistical model, a multidimensional latent growth model comes with certain requirements with respect to the data collection design. In order to measure growth, repeated measurements of the same set of individuals are required. Furthermore, the data collection design should be specified such that no individual is given the…

The purpose of this study was to examine how selected linguistic components (including consistency of relational terms and extraneous information) impact performance at each stage of mathematical word problem solving (comprehension, equation construction, and computation accuracy) among students with different levels of computation achievement. …

This paper estimates the marginal returns to college for individuals induced to enroll in college by different marginal policy changes. The recent instrumental variables literature seeks to estimate this parameter, but in general it does so only under strong assumptions that are tested and found wanting. We show how to utilize economic theory and…

In recent months a number of states, such as Tennessee, have considered tying teacher evaluations and tenure to student achievement as part of their Race to the Top plans. This research brief evaluates how well early-career performance signals teacher effectiveness after tenure. The brief presents selected findings from a larger study using North…

Apprentice and trainee data are reported by the State and Territory Training Authorities to NCVER (National Centre for Vocational Education Research) on a quarterly basis, starting at the September quarter of 1994. The set of data submitted that quarter is referred to as the National Apprentice and Trainee Collection 1. The sets of data submitted…

Clustering is one of the most common data mining tasks, used frequently for data organization and analysis in various application domains. Traditional machine learning approaches to clustering are fully automated and unsupervised where class labels are unknown a priori. In real application domains, however, some "weak" form of side…

Two people take turns selecting from an even number of items. Their relative preferences over the items can be described as a permutation, then tools from algebraic combinatorics can be used to answer various questions. We describe each person's optimal selection strategies including how each could make use of knowing the other's preferences. We…

The focus of this presidential address is on the contemporary treatment of reliability and validity in educational assessment. Highlights on reliability are provided under the classical true-score model using tools from latent trait modeling to clarify important assumptions and procedures for reliability estimation. In addition to reliability,…

In manufacturing today, nothing is more important than giving a customer a clear and straight-forward accounting of what their money has purchased. Many potentially promising return business orders are lost because of unclear, ambiguous, or improper billing. One of the best ways of resolving cost bargaining conflicts is by providing a…

This paper complements previous studies on the effects of health on wages by addressing the problems of unobserved heterogeneity, sample selection, and endogeneity in one comprehensive framework. Using data from the German Socio-Economic Panel (GSOEP), we find the health variable to suffer from measurement error and a number of tests provide…

Some scholars and policymakers who are concerned about the inequitable distribution of quality teachers suggest offering financial incentives for working in hard-to-staff schools. Previous studies have estimated compensating differentials using hedonic modeling, an approach potentially undermined by district-wide salary schedules and the lack of…

A standard topic in an advanced undergraduate classical mechanics course is the determination of the orbits in a gravitational field. In the present paper we report on the calculation of bound orbits in the gravitational field of a spiral galaxy. Calculations such as these could serve to focus attention on an area of cutting edge astrophysics and…

In this paper, the time required for a tower block to collapse is calculated. The tower collapses progressively, with one floor falling onto the floor below, causing it to fall. The rate of collapse is found to be not much slower than freefall. The calculation is an engaging and relevant application of Newton's laws, suitable for undergraduate…