Published: Nov 20, 2010 9:04 PM EST
Updated: Nov 20, 2010 6:04 PM EST

SEATTLE (AP) - Every year, American schools pay more than $8.6 billion in bonuses to teachers with master's degrees, even though the idea that a higher degree makes a teacher more effective has been mostly debunked.
      
For more than a decade, researchers have shown master's degree bonuses have little impact on student achievement. But state lawmakers and other officials have been reluctant to tackle this popular way for teachers to earn more money.
      
That could soon change, as local school districts around the country grapple with shrinking budgets.
      
Just this week, U.S. Education Secretary Arne Duncan said the economy has given the nation an opportunity to make dramatic changes in the productivity of its education system.