As part of the effort to change the nation's $2.6 trillion healthcare system, President Obama has proposed expanding comparative effectiveness research as a way to lower costs. Private medical groups, including Kaiser Permanente and the Mayo Clinic, have been comparing procedures for years. Because of studies conducted by the organization, Kaiser estimates that it saved $550,000 from 2001 through 2008 by reducing the number of joint replacement surgeries that had to be performed again.