They stop counting anyone unemployed  who has not actively looked for work in a year, i.e. the "DISCOURAGED AMERICAN WORKER". For unemployment catagories U1 through U6 these people just are not included.

link:http://www.financialsense.com/financial-sense-newshour/guest-expert/2012/05/08/john-williams/the-real-unemployment-rate-the-coming-fiscal-cliff

John Williams: The Real Unemployment Rate: 22%−Not 8.1%