Davide Dragone

We study income and price effects for intertemporal consumer problems with monetary and non-monetary dynamic constraints. We focus on short and long-run responses to a permanent change in income or price, and we characterize how such responses depend on the law of motion of non-monetary dynamic constraints and on time discounting. We provide a dynamic analog to the Slutsky equation, and we show the conditions under which the elasticity of demand to income or price is smaller in the long than in the short run, or even has opposite sign.

A subset of harm reduction strategies encourages individuals to switch from a harmful addictive good to a less harmful addictive good; examples include e-cigarettes (substitutes for combustible cigarettes) and methadone and buprenorphine (substitutes for opioids). Such harm reduction methods have proven to be controversial. Advocates argue that people struggling with addiction benefit because they can switch to a less harmful substance, but opponents argue that this could encourage abstainers to begin using the harm reduction method or even the original addictive good. This paper builds on theories of addiction to model the introduction of a harm reduction method, and it demonstrates the conditions under which each side is correct. The three key factors determining whether the introduction of a harm reduction method reduces or worsens health harms are: 1) the enjoyableness of the harm reduction method, 2) the addictiveness of the harm reduction method, and 3) the substitutability of the harm reduction method with the original addictive good. Knowledge of these conditions can help inform regulation of harm reduction methods. Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.

We study time preferences by means of a longitudinal lab experiment involving both monetary and non-monetary rewards (leisure). Our novel design allows to measure whether participants prefer to anticipate or delay gratification, without imposing any structural assumption on the instantaneous utility, intertemporal utility or the discounting functions. We find that most people prefer to anticipate monetary rewards (positive time preferences for money), but they delay non-monetary rewards (negative time preferences for leisure). These results cannot be explained by personal timetables and heterogeneous preferences only. They invite to reconsider the psychological interpretation of the discount factor, and suggest that the assumption that discounting is consistent across domains can lead to non-negligible prediction errors in models involving non-monetary decisions, such as labor supply models.

We consider a broad class of intertemporal economic problems and we characterize the short and long-run response of the demand for a good to a permanent increase in its market price. Depending on the interplay between self-productivity and time discounting, we show that dynamic substitution effects can generate price elasticities of opposite sign in the short and in the long run.

The milk addiction paradox refers to an empirical finding in which commodities that are typically considered to be non addictive, such as milk, appear instead to be addictive. This result seems more likely when there is persistence in consumption and when using aggregate data, and it suggests that the AR(2) model typically used in the addiction literature is prone to produce spurious result in favor of rational addiction. Using both simulated and real data, we show that the milk addiction paradox disappears when estimating the data using an AR(1) linear specification that describes the saddle-path solution of the rational addiction model. The AR(1) specification is able to correctly discriminate between rational addiction and simple persistence in the data, to test for the main features of rational addiction, and to produce unbiased estimates of the short and long-run elasticity of demand. These results hold both with individual and aggregated data, and they suggest that, for testing rational addiction, the AR(1) model is a better empirical alternative than the canonical AR(2) model.