Causal inference is a central topic in education research, although oftentimes it relies on observational studies, which makes causal identification methodologically challenging. This manuscript introduces causal graphs as a powerful language for elucidating causal theories and an effective tool for causal identification analysis. It discusses…

Enzymes are nature's catalysts, mediating chemical processes in living systems. The study of enzyme function and mechanism includes defining the maximum catalytic rate and affinity for substrate/s (among other factors), referred to as enzyme kinetics. Enzyme kinetics is a staple of biochemistry curricula and other disciplines, from molecular and…

The purpose of this study was to determine the effects of self-graphing on the writing of 3 fourth grade students with high-incidence disabilities. Measures of written expression included total number of words written and number of correct word sequences. During intervention, students self-graphed their total number of words written in response to…

This study investigated the accuracy of classroom teachers' judgments of the reading progress of their low-performing students. Participants were 36 second grade teachers and students in their lowest reading groups (n = 150). Student progress was monitored weekly using reading-curriculum-based measurement (R-CBM) procedures. After 6 weeks,…

Over the past decade, research on the use of technology in the mathematics classroom has focused primarily on issues of student learning and engagement. In this article, we focus on middle grades mathematics teachers' use of The Geometer's Sketchpad, and study both the decisions they make about when to use technology, and their motivations for…

In this essay, the author tries to look forward into the 21st century to divine three things: (i) What skills will researchers in the future need to solve the most pressing problems? (ii) What are some of the most likely candidates to be those problems? and (iii) What are some current areas of research that seem mined out and should not distract…

Multivalent relations, inferred as relationships with an added dimension of discernment, are realized as weighted graphs with multivalued edges. A unified treatment of the threshold problem is discussed and a reliability measure is produced to judge various partitions. (Author/EM)

Relations on a finite set V are viewed as weighted graphs. Using the language of graph theory, two methods of partitioning V are examined: selecting threshold values and applying them to a maximal weighted spanning forest, and using a parametric linear program to obtain a most adhesive partition. (Author/EM)

The aim of good data graphics is to display data accurately and clearly. This definition is used as a point of departure for developing 12 rules of bad data display: (1) show as little data as possible (minimize the data density); (2) hide what data you do show (minimize the data-ink ratio); (3) ignore the visual metaphor altogether; (4) only…

Four empirical laws of bibliometrics--anomalous number, Lotka's, Zipf's, and Bradford's--together with Laplace's "law of succession" and de Solla Price's cumulative advantage distribution are shown to be almost identical. A simple model shows that the frequency forms conform with inverse square law over appropriate interval. (Fifteen…

Numerical tables of mathematical functions are in continual demand by scientists and engineers for preliminary surveys of problems before programming for computing machines. This handbook was designed to provide scientific investigators with a comprehensive and self-contained summary of the mathematical functions that arise in physical and…

It is shown that Trueswell's empirical 80/20 rule arises from type of stochastic model for library loans presented by Burrell and Cane. Particular attention is paid to previously suggested uses of rule in identifying "core collection" for library noting that length of time period is of crucial importance. (20 references) (EJS)

Hammond's Cognitive Continuum theory posits that certain task features induce distinct processing modes (e.g., intuitive or analytic) and thus result in qualitatively different decision performance. Although the theory suggests the relation between task features and performance characteristics a priori, the validity of these predictions requires…

A statistical method is described and illustrated which provides confidence envelopes around item response functions. Examples of 95 percent confidence envelopes for the one-, two-, and three-parameter logistic response models are given. In addition, the authors describe N-line plots, which show the genesis of the envelope as well as the density…

One purpose for combining research studies is to estimate a population treatment effect. The internal validity of a model for how effect size estimates should be computed and combined will hinge upon the homogeneity of the effect size variation. Effect size variation may be assessed in the form of a summary fit statistic, and a direct…