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…

More than 1 million people have watched the online video in which Salman Khan--a charming MIT math whiz, Harvard Business School graduate, and former Boston hedge-fund analyst--explains how he began tutoring his cousins in math by posting short lessons for them on YouTube. Other people began watching the lessons and sending Khan adulatory notes.…