Few assets in the NBA are as valued as lottery picks as general managers go to great lengths to put pick protection on traded first rounders.

But there is evidence that they are not quite as valuable as perceived internally.

Of the 70 lottery picks between the 2004 NBA Draft and 2008 NBA Draft, 24 are already out of the NBA, representing 34 percent. This five-year sample covers Dwight Howard's draft class to the one headlined by Derrick Rose.