Federal Reserve Chair Janet Yellen speaks to graduates during New York University's commencement ceremony Wednesday, May 21, 2014, at Yankee Stadium in New York. (AP Photo/Frank Franklin II)
Federal Reserve Chair Janet Yellen waves to the crowd at New York University's commencement ceremony Wednesday, May 21, 2014, at Yankee Stadium in New York. (AP Photo/Frank Franklin II)
Low short-term interest rates will be needed for a "considerable time," Federal Reserve Chair Janet Yellen told the Joint Economic Committee of Congress on May 7. (AP Photo/Charles Dharapak)