Since 1950 capital gains have generally been taxed at a lower rate than income, to spur investment. Republican presidential candidate Mitt Romney wants to ditch capital gains tax altogether for people earning less than $250,000. Pres Obama, in his Affordable Care Act, increased the rate by 3.8% for high earners beginning in 2013, and has proposed the so-called Buffett Rule, which would among other things end an accounting interpretation that allows private equity and hedge fund managers to save money by paying tax on their earnings at the capital gains rate. But Leonard Burman, who teaches economics at Syracuse University's Maxwell School, presented a graph at the joint hearing of the Senate Finance and House Ways and Means Committees that plotted capital gains tax rates against economic growth from 1950 to 2011. He found no statistically significant correlation between the two.