This paper develops a dynamic programming model of the Social Security Disability Insurance (SSDI) application timing decision. We estimate the time to application from the point at which a health condition first begins to affect the kind or amount of work that a currently employed person can...

Using a selection bias correction model with ordered probit, we estimate how a second semester of calculus affects students' grades in intermediate economic theory. Selection bias correction is needed because similar aptitudes and interests often lead students to enroll and do well in both...