In this paper, we present an analysis of the Arkansas Teacher Retirement System (ATRS) pension plan and an empirical investigation of the behavioral response to that plan, as well as to a possible reform plan. We begin by describing the plan parameters and discussing the incentives these parameters create. We then estimate the effect of pension…

The 2003 National Assessment of Adult Literacy (NAAL) assessed the English literacy skills of a nationally representative sample of 18,500 U.S. adults (age 16 and older) residing in private households. NAAL is the first national assessment of adult literacy since the 1992 National Adult Literacy Survey (NALS). The NAAL and NALS produced direct…

Non-random assignment of students to teachers can bias value added estimates of teachers' causal effects. Rothstein (2008a, b) shows that typical value added models indicate large counter-factual effects of 5th grade teachers on students' 4th grade learning, indicating that classroom assignments are far from random. This paper quantifies the…

The purpose of this study was to develop an IRT model that would enable the estimation of decision indices based on composite scores. The composite scores, defined as a combination of unidimensional test scores, were either a total raw score or an average scale score. Additionally, estimation methods for the normal and compound multinomial models…

When seasonal journeys take place in nature, birds and fishes migrate in groups. This provides them not only with security but also a considerable saving of energy. The power they need to travel requires overcoming aerodynamic or hydrodynamic drag forces, which can be substantially reduced when the group travels in an optimal arrangement. Also in…

When pre-school children count an array of objects containing one that is broken in half, most count the halves as two separate objects. Two studies explore this predisposition to count discrete physical objects (DPOs) and investigate its robustness in the face of various manipulations. In Experiment 1, 32 children aged three-four years counted…

In multilevel structural equation modeling, the "standard" approach to evaluating the goodness of model fit has a potential limitation in detecting the lack of fit at the higher level. Level-specific model fit evaluation can address this limitation and is more informative in locating the source of lack of model fit. We proposed level-specific test…

Division-With-Remainder (DWR) problems are particularly complex, as suggested in many studies. The purpose of this work was to establish whether students' difficulties in DWR problems came from an inadequate initial representation or from an inadequate final interpretation of the numerical answers, and whether remainders could be grouped into two…

The nonlinear mixed effects model for continuous repeated measures data has become an increasingly popular and versatile tool for investigating nonlinear longitudinal change in observed variables. In practice, for each individual subject, multiple measurements are obtained on a single response variable over time or condition. This structure can be…

Recent studies have documented an evolutionarily primitive, early emerging cognitive system for the mental representation of numerical quantity (the analog magnitude system). Studies with nonhuman primates, human infants, and preschoolers have shown this system to support computations of numerical ordering, addition, and subtraction involving…

Common rates employed in classificatory testing are the true positive rate (TPR), false positive rate (FPR), positive predictive power (PPP), and negative predictive power (NPP). FPR and TPR are estimated from research samples representing populations to be distinguished by classificatory testing. PPP and NPP are used by clinicians to classify…

Previous studies have suggested that children's learning of the relation between number words and approximate numerosities depends on their verbal counting ability, and that children exhibit no knowledge of mappings between number words and approximate numerical magnitudes for number words outside their productive verbal counting range. In the…

This study examines model selection indices for use with dichotomous mixture item response theory (IRT) models. Five indices are considered: Akaike's information coefficient (AIC), Bayesian information coefficient (BIC), deviance information coefficient (DIC), pseudo-Bayes factor (PsBF), and posterior predictive model checks (PPMC). The five…

In order for school professionals to make informed decisions about appropriate interventions, it is imperative that they are informed as to what is available to aid students. The purpose of the present literature review was to examine specific interventions that could be employed with students identified as needing additional support in…

A number of schools have recently introduced new courses dealing with various aspects of iteration theory or at least have found ways of including topics such as chaos and fractals in existing courses. In this note, we will consider a family of functions whose members are especially well suited to illustrate many of the concepts involved in these…