英文文献：Two-Stage Estimation to Control for Unobservables in a Recreation Demand Model with Unvisited Sites
英文文献作者：Melstrom, Richard T.,Jayasekera, Deshamithra H.W.
英文文献摘要：
The role of unobserved site attributes is a growing concern in recreation demand modeling. One solution in random utility models (RUM) involves separating estimation into two stages, where the RUM model is estimated with alternative-specific constants (ASCs) in the first stage, and the estimated ASCs are regressed on the observed site attributes in the second stage. Prior work estimates the second stage with OLS and 2SLS regression. We present an application with censored regression in the second stage. We show OLS produces inconsistent parameters when there are unvisited sites with no estimable ASCs and that censored regression avoids this problem.