Randomized experiments are often seen as the "gold standard" for causal research. Despite the fact that experiments use random assignment to treatment conditions, units are seldom selected into the experiment using probability sampling. Very little research on experimental design has focused on how to make generalizations to well-defined…

Ninth grade Elementary Secondary Education Act (ESEA) Title I evaluation results in reading and English-writing projects were compared, using the RMC Model A with local empirical norms, Model A with national interpolated norms, and Model B. The Comprehensive Tests of Basic Skills (CTBS)--Total Reading and Total Language subtests--were administered…