in his answer to the 6th annual edge question, mit professor of psychology steven pinker writes: … little in instructional practice has been evaluated using the standard paraphernalia of social science—control groups, random assignment, data collection, statistics. Instead, classroom practice is set by fads, romantic theories, slick packages, and political crusades. i would note that educational software is much the same, unfortunately. (or at least it was a few years ago, and i assume little has changed since then.) i think an educational software company that actually invested in even minimal research to support the efficacy of its products would find that investment repaid in the marketing value of that information. and they may even end up with better products. (link to pinker's answer via the volokh conspiracy.)