In educational effectiveness research, it frequently has proven difficult to make credible inferences about cause and effect relations. The article first identifies the main categories of threats to valid causal inference from observational data, and discusses designs and analytic approaches which protect against them. With the use of data from 22…

This study of thirteen-year-old students from Hong Kong assessed the efficacy of several different instructional activities using data from the Third International Mathematics and Science Study (TIMSS). Discusses teaching activities, homework activities, classroom activities, and cooperative learning. Six tables of data are appended. (Contains 24…