Knowledge that Transforms

We investigate learning by doing using detailed data from a major auto producer’s assembly plant. We focus on the acquisition, aggregation, transmission, and embodiment of the knowledge stock built through learning. We find that most knowledge was not retained by plant workers despite their importance as a learning conduit. This is consistent with the plant’s systems for productivity measurement and improvement. We further explore how learning at the hundreds of processes along the production line undergirds plantwide productivity. Our results shed light on how productivity gains accrue at the plant level and how firms apply managerial inputs to expand production.

We propose a methodology for studying changes in bilateral commodity trade due to goods not exported previously or exported only in small quantities. Using a panel of 1,900 country pairs, we find that increased trade of these “least-traded goods” is an important factor in trade growth. This extensive margin accounts for 10 percent of the growth in trade for NAFTA country pairs, for example, and 26 percent in trade between the United States and Chile, China, and Korea. Looking at country pairs with no major trade policy change or structural change, however, we find little change in the extensive margin.

Economic variables move asymmetrically over the business cycle: quickly during crises but slowly during recoveries. I show that this asymmetry is stronger in countries with less developed financial systems and greater financial frictions. Then I explain this fact using a learning model with endogenous information about economic conditions. Financial frictions, which I capture by higher bankruptcy costs, magnify the reaction of lending rates and economic activity to negative shocks and then delay their recovery by restricting information after the crisis. Empirical evidence and a quantitative exploration of the model show that this explanation is consistent with the data.

This paper provides a theoretical foundation that supports the degressive proportionality principle in apportionment problems, such as the allocation of seats in a federal parliament. The utility assigned by an individual to a constitutional rule is a function of the frequency with which each collective decision matches the individual’s own will. The core of the argument is that, if the function is concave, then classical utilitarianism at the social level recommends decision rules that exhibit degressive proportionality with respect to the population size.

This paper explores the economics of diversity-enhancing policies. A model is proposed in which heterogeneous agents, distinguished by skill level and social identity, purchase productive opportunities in a competitive market. We analyze policies designed to raise the status of a disadvantaged identity group. When agent identity is contractible, efficient policy grants preferred access to slots but offers no direct assistance for acquiring skills. When identity is not contractible, efficient policy provides universal subsidies to skill development when the fraction of the disadvantaged group at the skill development margin is larger than their share at the slot assignment margin.

We study models of credit with limited commitment, which implies endogenous borrowing constraints. We show that there are multiple stationary equilibria, as well as nonstationary equilibria, including some that display deterministic cyclic and chaotic dynamics. There are also stochastic (sunspot) equilibria, in which credit conditions change randomly over time, even though fundamentals are deterministic and stationary. We show this can occur when the terms of trade are determined by Walrasian pricing or by Nash bargaining. The results illustrate how it is possible to generate equilibria with credit cycles (crunches, freezes, crises) in theory, and as recently observed in actual economies.

Assuming Brownian/Poisson uncertainty, a certainty equivalent (CE) based on the smooth second-order expected utility of Klibanoff, Marinacci, and Mukerji is shown to be approximately equal to an expected-utility CE. As a consequence, the corresponding continuous-time recursive utility form is the same as for Kreps-Porteus utility. The analogous conclusions are drawn for a smooth divergence CE, based on a formulation of Maccheroni, Marinacci, and Rustichini, but only under Brownian uncertainty. Under Poisson uncertainty, a smooth divergence CE can be approximated with an expected-utility CE if and only if it is of the entropic type. A nonentropic divergence CE results in a new class of continuous-time recursive utilities that price Brownian and Poissonian risks differently.