Knowledge that Transforms

This paper develops a dynamic general equilibrium model of an agricultural economy in which poor farmers borrow from rich farmers. Because output is stochastic (we allow for idiosyncratic and aggregate shocks), there may be default ex post. We compare equilibria with and without political intervention. Intervention takes the form of a moratorium and is decided by voting. When bad economic shocks are highly likely, state‐contingent debt moratoria always improve ex post efficiency and may also improve ex ante efficiency. Moreover, the threat of moratoria enhances efficiency. When adverse macro shocks are unlikely, state‐contingent moratoria always improve ex ante welfare by completing incomplete debt contracts.

Once the zero bound on nominal interest rates is taken into account, Taylor‐type interest rate feedback rules give rise to unintended self‐fulfilling decelerating inflation paths and aggregate fluctuations driven by arbitrary revisions in expectations. These undesirable equilibria exhibit the essential features of liquidity traps since monetary policy is ineffective in bringing about the government’s goals regarding the stability of output and prices. This paper proposes several fiscal and monetary policies that preserve the appealing features of Taylor rules, such as local uniqueness of equilibrium near the inflation target, and at the same time rule out the deflationary expectations that can lead an economy into a liquidity trap.

Empirical work testing for a negative trade-off between risk and incentives has not had much success: the data suggest a positive relationship between measures of uncertainty and incentives rather than the posited negative trade-off. I argue that the existing literature fails to account for an important effect of uncertainty on incentives through the allocation of responsibility to employees. When workers operate in certain settings, firms are content to assign tasks to workers and monitor their inputs. By contrast, when the situation is more uncertain, they delegate responsibility to workers but, to constrain their discretion, base compensation on observed output.

The Internet may significantly reduce search costs by enabling price comparisons on-line. This paper provides empirical evidence on how Internet comparison shopping sites affected the prices of life insurance in the 1990s. With micro data on individual insurance policies and with individual and policy characteristics controlled for, hedonic-type regressions show that increases in Internet use significantly reduced the price of term life insurance. Further evidence shows that prices did not fall with rising Internet usage in the period before the sites began, nor for insurance types that were not covered on the sites. The results suggest that the growth of the Internet has reduced term life prices by 815 percent. The results also show that the initial introduction of the Internet search sites is initially associated with an increase in price dispersion within demographic groups, but as use spreads, the dispersion falls.

The fraction of U.S. college graduate women entering professional programs increased substantially just after 1970, and the age at first marriage among all U.S. college graduate women began to soar around the same year. We explore the relationship between these two changes and the diffusion of the birth control pill ("the pill") among young, unmarried college graduate women. Although the pill was approved in 1960 by the Food and Drug Administration and spread rapidly among married women, it did not diffuse among young, single women until the late 1960s after state law changes reduced the age of majority and extended "mature minor" decisions. We present both descriptive time series and formal econometric evidence that exploit cross-state and cross-cohort variation in pill availability to young, unmarried women, establishing the "power of the pill" in lowering the costs of long-duration professional education for women and raising the age at first marriage.

This paper proposes a technique for obtaining more precise estimates of demand and supply curves when one is constrained to market-level data. The technique allows one to augment market share data with information relating consumer demographics to the characteristics of the products they purchase. This extra information plays the same role as consumer-level data, allowing estimated substitution patterns and (thus) welfare to directly reflect demographic-driven differences in tastes for observed characteristics. I apply the technique to the automobile market, estimating the economic effects of the introduction of the minivan. I show that models estimated without micro data yield much larger welfare numbers than the model using them, primarily because the micro data appear to free the model from a heavy dependence on the idiosyncratic logit "taste" error. I complete the welfare picture by measuring the extent of first-mover advantage and profit cannibalization both initially by the innovator and later by the imitators. My results support a story in which large improvements in consumers' standard of living arise from competition as firms cannibalize each other's profits by seeking new goods that give them some temporary market power.

The lumpiness of investment activity at the plant level is a well‐established fact. Previous research has suggested that such discrete and occasional adjustments have significant aggregate implications. In particular, it has been argued that changes in plants’ willingness to invest in response to aggregate shocks can at times generate large movements in total investment demand. In this study, I reassess these predictions in a general equilibrium environment. Specifically, assuming nonconvex costs of capital adjustment, I derive generalized (S, s) adjustment rules yielding lumpy plant‐level investment within an otherwise standard equilibrium business cycle model. In contrast to previous partial equilibrium analyses, model results reveal that the aggregate effects of lumpy investment are negligible. In general equilibrium, households’ preference for relatively smooth consumption profiles offsets changes in aggregate investment demand implied by the introduction of lumpy plant‐level investment. As a result, adjustments in wages and interest rates yield quantity dynamics that are virtually indistinguishable from the standard model, and lumpy investment appears largely irrelevant for equilibrium business cycle analysis.

We present evidence that the equity premium and the premium of value stocks over growth stocks are consistent in the 198296 period with a stochastic discount factor calculated as the weighted average of individual households' marginal rate of substitution with low and economically plausible values of the relative risk aversion coefficient. Since these premia are not explained with an SDF calculated as the per capita marginal rate of substitution with a low value of the RRA coefficient, the evidence supports the hypothesis of incomplete consumption insurance. We also present evidence that an SDF calculated as the per capita marginal rate of substitution is better able to explain the equity premium and does so with a lower value of the RRA coefficient, as the definition of asset holders is tightened to recognize the limited participation of households in the capital market.