“…Indeed, a large literature, going back at least to Hausman (1985), develops methods that address the difficulties that arise in modeling selection and utilization under non-linear budget sets, and applies these methods to other settings in which similar non-linearities are common, such as labor supply (Burtless and Hausman, 1978; Blundell and MaCurdy, 1999; Chetty et al, 2011), electricity utilization (Reiss and White, 2005), and cellular phones (Grubb and Osborne, forthcoming; Yao et al, 2012). …”