An appropriate estimate of statistical power is critical for the design of intervention studies. Although the inclusion of a pretest covariate in the test of the primary outcome can increase statistical power, samples selected on the basis of pretest performance may demonstrate range restriction on the selection measure and other correlated…

This paper provides practical guidance for researchers who are designing and analyzing studies that randomize schools--which comprise three levels of clustering (students in classrooms in schools)--to measure intervention effects on student academic outcomes when information on the middle level (classrooms) is missing. This situation arises…

The Rasch model was used to equate reading comprehension tests of widely different difficulty for three groups of fifth grade students of widely different ability. Under these extreme circumstances, the Rasch model equating was unsatisfactory. (Author/CTM)

Accurate estimation of variance components used in generalizability theory is essential for the theory to be viewed as an efficacious mechanism for studying the reliability and validity of a measurement procedure. This paper explores two alternatives for dealing with the apparent instability of small sample size used in determining the accuracy of…

The Anchor Test Study provides a method for translating a pupil's score on any one of eight widely used standardized reading tests for Grades 4, 5, and 6 to a corresponding score on any of the other seven tests, as well as furnishing new nationally representative norms for each of the eight tests. In addition, the Study presents new estimates of…

In 1982, the Educational Testing Service (ETS) proposed to implement a new, complex design for the National Assessment of Educational Progress (NAEP). The major features of this design are described in "A New Design for a New Era" (Messick, Beaton, and Lord, 1983). The purpose of this document is to describe the actual implementation of…

The Anchor Test Study provides a method for translating a pupil's score on any one of eight widely used standardized reading tests for Grades 4, 5, and 6 to a corresponding score of any of the other seven tests, as well as furnishing new nationally representative norms for each of the eight tests. In addition, the Study presents new estimates of…