With an educational issue that has caught the attention of many countries in the world (study load), a population of 8th graders from a typical Chinese metropolitan city (40,536 from 118 schools), and an advanced statistical strategy (multilevel piecewise regression), we examined whether there was a turning point in terms of the effects of study…

Many inquiries regarding the causal effects of policies or programs are based on research designs where the treatment assignment process is unknown, and thus valid inferences depend on tenuous assumptions about the assignment mechanism. This article draws attention to the importance of understanding the assignment mechanism in policy and program…

Objectives: Group-randomized designs are well suited for studies of professional development because they can accommodate programs that are delivered to intact groups (e.g., schools), the collaborative nature of professional development, and extant teacher/school assignments. Though group designs may be theoretically favorable, prior evidence has…

Background: Cluster-randomized experiments that assign intact groups such as schools or school districts to treatment conditions are increasingly common in educational research. Such experiments are inherently multilevel designs whose sensitivity (statistical power and precision of estimates) depends on the variance decomposition across levels.…

The authors use Canadian data from the Third International Mathematics and Science Study to examine six instructional methods that mathematics teachers use to introduce new topics in mathematics on performance of eighth-grade students in six mathematical areas (mathematics as a whole, algebra, data analysis, fraction, geometry, and measurement).…

A study involving 34 Dutch eighth-grade teachers and their classes explored the accuracy, reliability, and predictive validity of a logbook procedure for assessing the opportunity to learn mathematics. Results suggest that the logbook approach is reliable and that the variables measured are good predictors of the learning progress. (SLD)

The prevalence of invalid reports of cigarette smoking initiation (reporting smoking at one point and denying it at another) was studied, with 2,597 seventh- and eighth-grade students questioned. About 4% of the sample provided inconsistent responses, a rate that justifies concern about self-report accuracy. (SLD)

An example is provided of an evaluation in which the formulation of explicit decision rules was a central activity. The case for and against the use of decision rules in program evaluation is considered, and the appropriate context identified. Implications for the rights of decision makers are addressed. (Author/CTM)