This article develops new closed-form variance expressions for power analyses for commonly used difference-in-differences (DID) and comparative interrupted time series (CITS) panel data estimators. The main contribution is to incorporate variation in treatment timing into the analysis. The power formulas also account for other key design features…

Although evaluators often use an interrupted time series (ITS) design to test hypotheses about program effects, there are few empirical tests of the design's validity. We take a randomized experiment on an educational topic and compare its effects to those from a comparative ITS (CITS) design that uses the same treatment group as the experiment…

The purpose of this study is to describe an alternative means of estimating school effectiveness, referred to as an "absolute year" of schooling and demonstrate its usefulness as a measure of school effectiveness in the middle grades. More specifically, the study investigated (a) whether the absolute schooling effect in math and reading outcomes…

Detecting early signs of autism is essential for timely diagnosis and initiation of effective interventions. Several research groups have initiated prospective studies of high-risk populations including infant siblings, to systematically collect data on early signs within a longitudinal design. Despite the potential advantages of prospective…

In this article, we argue that educational technology research has spent too long trapped in a paradigm of simplistic comparisons, wherein normal science consists of evaluating a technology-based intervention by contrasting it with some established set of educational practices. Our argument is different in significant ways from the claim that…

In this paper, the efficiency of conditional maximum likelihood (CML) and marginal maximum likelihood (MML) estimation of the item parameters of the Rasch model in incomplete designs is investigated. The use of the concept of F-information (Eggen, 2000) is generalized to incomplete testing designs. The scaled determinant of the F-information…

A set procedure developed in this study is useful in determining sample size, based on specification of linear contrasts involving certain formula treatments. (Author/DEP)

This technical document, part of a series of chapters described in SO 011 759, describes a basic model of panel analysis used in a study of the causes of institutional and structural change in nations. Panel analysis is defined as a record of state occupancy of a sample of units at two or more points in time; for example, voters disclose voting…

This document is part of a series of chapters described in SO 011 759. Addressing the question of effective models to measure change and the change process, the author suggests that linear structural equation systems may be viewed as steady state outcomes of continuous-change models and have rich sociological grounding. Two interpretations of the…

This document is part of a series of chapters described in SO 011 759. Stochastic models for the sociological analysis of change and the change process in quantitative variables are presented. The author lays groundwork for the statistical treatment of simple stochastic differential equations (SDEs) and discusses some of the continuities of…

This document is part of a series of chapters described in SO 011 759. Addressing the problems of studying change and the change process, the report argues that sociologists should study coupled changes in qualitative and quantitative outcomes (e.g., marital status and earnings). The author presents a model for sociological studies of change in…

The document, part of a series of chapters described in SO 011 759, examines sociological research methods for the study of change. The advantages and procedures for dynamic analysis of event-history data (data giving the number, timing, and sequence of changes in a categorical dependent variable) are considered. The authors argue for grounding…

This study by two Ph.D. students in library science reviewed a systematic sample of the research literature in library and information science published in 62 core library journals in 1983 to order to identify substantive articles and compare their findings on research methodologies and trends with those reported in a similar study performed in…

Several sampling procedures for collecting observational data on student activities were studied in an effort to determine their relative efficiency. The setting was a fifth grade Individually Prescribed Instruction (IPI) mathematics class of thirty-three pupils. A criterion measure was obtained by cumulating the measurements obtained on the…