This supplement contains documentation on the explicit and implicit stratification variables included in the TIMSS 2011 data files. The explicit strata are smaller sampling frames, created from the national sampling frames, from which national samples of schools were drawn. The implicit strata are nested within the explicit strata, and were used…

Is the United States getting it wrong when it comes to educating tomorrow's innovators in critical fields? It has been known for years that the only way to compete globally in information technology, engineering, nanotechnology, robotics and other fields is to give students the best educational opportunities possible. But do individuals have a…