@techreport{NBERt0166,
 title = "Accounting for Dropouts in Evaluations of Social Experiments",
 author = "James Heckman and Jeffrey Smith and Christopher Taber",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Technical Working Paper Series",
 number = "166",
 year = "1994",
 month = "September",
 URL = "http://www.nber.org/papers/t0166",
 abstract = {This paper considers the statistical and economic justification for one widely-used method of adjusting data from social experiments to account for dropping-out behavior due to Bloom (1984).  We generalize the method to apply to distributions not just means, and present tests of the key identifying assumption in this context.  A reanalysis of the National JTPA experiment base vindicates application of Bloom's method in this context.},
}