It has long been thought that the United States education system is the great equalizer, lifting less advantaged children out of poverty and improving their chances for success in adulthood. The opportunity for economic and social mobility depends heavily, however, on access to high quality education. Recent research has raised concerns about…

Replication of the Second International Mathematics Study (SIMS) in Ontario, Canada, is described and assessed. The curriculum and testing program covers numerical methods, geometry, and algebra. Whereas classical studies focused on mean scores of a system's students and on percentages of teachers for opportunity to learn (OTL), SIMS aggregates…