Martin S. Feldstein, a conservative Harvard economist and a former chief economic advisor in the Reagan administration, who was unafraid to publicly disagree with fellow White House officials, died June 11. He was 79.

Professor Feldstein had a long career teaching at Harvard. He later counseled the administrations of George W. Bush and Barack Obama and for three decades, from 1977 to 2008, was president of the National Bureau of Economic Research that under his leadership became a gathering point for economists, particularly those focused on policy-oriented work.