@techreport{NBERw9055,
 title = "The Evidence on Credit Constraints in Post-Secondary Schooling",
 author = "Pedro Carneiro and James J. Heckman",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "9055",
 year = "2002",
 month = "July",
 URL = "http://www.nber.org/papers/w9055",
 abstract = {This paper examines the family income -- college enrollment relationship and the evidence on credit constraints in post-secondary schooling. We distinguish short-run liquidity constraints from the long-term factors that promote cognitive and noncognitive ability. Long-run factors crystallized in ability are the major determinants of the family income -- schooling relationship, although there is some evidence that up to 8% of the U.S. population is credit constrained in a short-run sense. Evidence that IV estimates of the returns to schooling exceed OLS estimates is sometimes claimed to support the existence of substantial credit constraints. This argument is critically examined.},
}