Common standards for what students should learn in English and math each year from kindergarten through high school were released less than two months ago, The New York Times reported Wednesday.
"This has been the third rail of education, and the fact that you're now seeing half the nation decide that it's the right thing to do is a game changer," Duncan said.
States that adopt the standards by Aug. 2 win points in the Obama administration's Race to the Top competition that will spread $3.4 billion to winners in September.
The development of national education standards was aided by financial backing from the Bill & Melinda Gates Foundation.
Two years in the making, they lay out detailed expectations of skills students need to achieve at each grade level.