@article{Burke:143014,
      recid = {143014},
      author = {Burke, William J.},
      title = {Fitting and interpreting Cragg's tobit alternative using  Stata},
      journal = {Stata Journal},
      address = {2009},
      number = {199-2016-2661},
      pages = {9},
      year = {2009},
      abstract = {In this article, I introduce the user-written command  craggit, which simultaneously fits both tiers of Cragg’s  (1971, Econometrica 39: 829–844) “twotier” (sometimes  called “two-stage” or “double-hurdle”) alternative to tobit  for corner-solution models. A key limitation to the tobit  model is that the probability of a positive value and the  actual value, given that it is positive, are determined by  the same underlying process (i.e., the same parameters).  Cragg proposed a more flexible alternative that allows  these outcomes to be determined by separate processes  through the incorporation of a probit model in the first  tier and a truncated normal model in the second. Also,  tobit is nested in craggit, making the latter a popular  choice among “two-tier” models. In the article, I also  present postestimation syntax to facilitate the  understanding and interpretation of results.},
      url = {http://ageconsearch.umn.edu/record/143014},
      doi = {https://doi.org/10.22004/ag.econ.143014},
}