NBER Publications by Martin Weitzman

Using climate change as a prototype motivating example, this paper analyzes the implications of structural uncertainty for the economics of low-probability high-impact catastrophes. The paper shows that having an uncertain multiplicative parameter, which scales or amplifies exogenous shocks and is updated by Bayesian learning, induces a critical "tail fattening" of posterior-predictive distributions. These fattened tails can have strong implications for situations (like climate change) where a catastrophe is theoretically possible because prior knowledge cannot place sufficiently narrow bounds on overall damages. The essence of the problem is the difficulty of learning extreme-impact tail behavior from finite data alone. At least potentially, the influence on cost-benefit analysis of fat-t...

Using only information based on current directly-observable market behavior, the paper shows how to make rigorous dynamic welfare comparisons among economies or economic situations having arbitrarily-different endowments and technologies, but sharing a common dynamic preference ordering. The correct answers to seemingly complicated questions, which intrinsically involve comparing wealth-like measures of dynamic well-being, can be translated isomorphically into a simple-minded story told in the familiar language of old-fashioned static consumer-welfare theory.

Japan has a relatively unique system of labor compensation. Most Japanese workers are paid large bonuses twice a year. This paper examines the cyclical movement of bonuses compared with wages and the relation of bonuses to employment in the context of the Weitzman "share economy." The paper makes three basic points:(1) The Japanese bonus is much more pro-cyclical than Japanese base wages,but not as cyclically variable as profits. Bonuses can be interpreted as containing a quantitatively significant revenue or profit-sharing component.(2) Bonuses have quite different employment consequences than do base wages. Even after controlling for other economic factors, bonuses are positively related to employment, whereas base wages are negatively related to employment.(3) The bonus system of paying...