Knowledge that Transforms

This paper asks how a household should choose between a fixed-rate (FRM) and an adjustable-rate (ARM) mortgage. In an environment with uncertain inflation a nominal FRM has a risky real capital value, whereas an ARM has a stable real capital value but short-term variability in required real payments. Numerical solution of a life-cycle model with borrowing constraints and income risk shows that an ARM is generally attractive, but less so for a risk-averse household with a large mortgage, risky income, high default cost, or low moving probability. An inflation-indexed FRM can improve substantially on standard nominal mortgages.

Between 1984 and 2001, the share of nonelderly adults receiving Social Security Disability Insurance income (DI) rose by 60 percent to 5.3 million beneficiaries. Rapid program growth despite improving aggregate health appears to be explained by reduced screening stringency, declining demand for less skilled workers, and an unforeseen increase in the earnings replacement rate. We estimate that the sum of these forces doubled the labor force exit propensity of displaced high school dropouts after 1984, lowering measured U. S. unemployment by one-half a percentage point. Steady state calculations augur a further 40 percent increase in the rate of DI receipt.

This paper studies whether agents must agglomerate at a single location in a class of models of two-sided interaction. In these models there is an increasing returns effect that favors agglomeration, but also a crowding or market-impact effect that makes agents prefer to be in a market with fewer agents of their own type. We show that such models do not tip in the way the term is commonly used. Instead, they have a broad plateau of equilibria with two active markets, and tipping occurs only when one market is below a critical size threshold. Our assumptions are fairly weak, and are satisfied in Krugman's model of labor market pooling, a heterogeneous-agent version of Pagano's asset market model, and Ellison, Fudenberg, and Möbius' model of competing auctions.

Recent immigrants tend to locate in ethnic “enclaves” within metropolitan areas. The economic consequence of living in such enclaves is still an unresolved issue. We use data from an immigrant policy initiative in Sweden, when government authorities distributed refugee immigrants across locales in a way that we argue is exogenous. This policy initiative provides a unique natural experiment, which allows us to estimate the causal effect on labor market outcomes of living in enclaves. We find substantive evidence of sorting across locations. When sorting is taken into account, living in enclaves improves labor market outcomes for less skilled immigrants: the earnings gain associated with a standard deviation increase in ethnic concentration is 13 percent. Furthermore, the quality of the enclave seems to matter. Members of high-income ethnic groups gain more from living in an enclave than members of low-income ethnic groups.

People exaggerate the degree to which their future tastes will resemble their current tastes. We present evidence from a variety of domains which demonstrates the prevalence of such projection bias, develop a formal model of it, and use this model to demonstrate its importance in economic environments. We show that, when people exhibit habit formation, projection bias leads people to consume too much early in life, and to decide, as time passes, to consume more—and save less—than originally planned. Projection bias can also lead to misguided purchases of durable goods. We discuss a number of additional applications and implications.

Roughly one-third of world trade is intrafirm trade. This paper starts by unveiling two systematic patterns in the volume of intrafirm trade. In a panel of industries, the share of intrafirm imports in total U.S. imports is significantly higher, the higher the capital intensity of the exporting industry.

In many countries, banks lend to firms controlled by the bank's owners. We examine the benefits of related lending using a newly assembled data set for Mexico. Related lending is prevalent (20 percent of commercial loans) and takes place on better terms than arm's-length lending (annual interest rates are 4 percentage points lower). Related loans are 33 percent more likely to default and, when they do, have lower recovery rates (30 percent less) than unrelated ones. The evidence for Mexico in the 1990s supports the view that in some important settings related lending is a manifestation of looting.

We propose a boundedly rational model of opinion formation in which individuals are subject to persuasion bias; that is, they fail to account for possible repetition in the information they receive. We show that persuasion bias implies the phenomenon of social influence, whereby one's influence on group opinions depends not only on accuracy, but also on how well-connected one is in the social network that determines communication. Persuasion bias also implies the phenomenon of unidimensional opinions; that is, individuals' opinions over a multidimensional set of issues converge to a single “left-right” spectrum. We explore the implications of our model in several natural settings, including political science and marketing, and we obtain a number of novel empirical implications.