This report synthesizes what research says works in improving teacher skills and knowledge, what nations that outperform the United States in education are doing, and provides an analysis of newly available data from the federal Schools and Staffing Survey and other sources to indicate where the nation stands in building the capacity of educators to help students reach high standards. It includes newly analyzed data from the federal Schools and Staffing Survey and other data sources. Contents include: (1) Introduction; (2) Defining Effective Professional Development; (3) Professional Development in the U.S. and Abroad; (4) The Status of Professional Learning Opportunities in the U.S.; and (5) Another Lens on Professional Learning Opportunities: The NSDC Standards Assessment Inventory. Appended are: (1) Datasets and Methods; (2) Results from the 2003-04 Schools and Staffing Survey; and (3) Results from the 2007-08 Standards Assessment Inventory. (Contains 49 tables.)