Knowledge that Transforms

This paper investigates the dynamics of individual portfolios in a unique data set containing the disaggregated wealth of all households in Sweden. Between 1999 and 2002, we observe little aggregate rebalancing in the financial portfolio of participants. These patterns conceal strong household-level evidence of active rebalancing, which on average offsets about one-half of idiosyncratic passive variations in the risky asset share. Wealthy, educated investors with better diversified portfolios tend to rebalance more actively. We find some evidence that households rebalance toward a greater risky share as they become richer. We also study the decisions to trade individual assets. Households are more likely to fully sell directly held stocks if those stocks have performed well, and more likely to exit direct stockholding if their stock portfolios have performed well; but these relationships are much weaker for mutual funds, a pattern that is consistent with previous research on the disposition effect among direct stockholders and performance sensitivity among mutual fund investors. When households continue to hold individual assets, however, they rebalance both stocks and mutual funds to offset about one-sixth of the passive variations in individual asset shares. Households rebalance primarily by adjusting purchases of risky assets if their risky portfolios have performed poorly, and by adjusting both fund purchases and full sales of stocks if their risky portfolios have performed well. Finally, the tendency for households to fully sell winning stocks is weaker for wealthy investors with diversified portfolios of individual stocks.

We test whether textbook consumers are forward-looking, using a large new data set on textbooks sold in college bookstores during the ten semesters from 1997 to 2001. The data strongly support the hypothesis that students are forward-looking with low short-run discount rates and that they behave as if they have rational expectations of publishers' revision behavior. Data from a second new data set on the market prices of used books at Amazon Marketplace also support the hypothesis of rational, forward-looking behavior. Simulation results indicate that students are sufficiently forward-looking that publishers cannot consistently raise revenue by accelerating current revision cycles.

Using nationally representative data on consumption, we show that Blacks and Hispanics devote larger shares of their expenditure bundles to visible goods (clothing, jewelry, and cars) than do comparable Whites. These differences exist among virtually all subpopulations, are relatively constant over time, and are economically large. Although racial differences in utility preference parameters might account for a portion of these consumption differences, we emphasize instead a model of status seeking in which conspicuous consumption is used as a costly indicator of a household's economic position. Using merged data on race- and state-level income, we demonstrate that a key prediction of the status-signaling model—that visible consumption should be declining in reference group income—is strongly borne out in the data for each racial group. Moreover, we show that accounting for differences in reference group income characteristics explains most of the racial difference in visible consumption.

Theory suggests that longer life expectancy encourages educational investment because a longer time horizon increases the value of investments that pay out over time. To estimate the magnitude of this effect, we examine a sudden drop in maternal mortality in Sri Lanka between 1946 and 1953, which sharply increased the life expectancy of girls. We assess whether girls' education relative to boys' increases more in areas with larger maternal mortality declines. We find that for every extra year of life expectancy, literacy increases by 0.7 percentage points (2%) and years of education increase by 0.11 years (3%).

Laboratory experiments in psychology find that media violence increases aggression in the short run. We analyze whether media violence affects violent crime in the field. We exploit variation in the violence of blockbuster movies from 1995 to 2004, and study the effect on same-day assaults. We find that violent crime decreases on days with larger theater audiences for violent movies. The effect is partly due to voluntary incapacitation: between 6 p.m. and 12 a.m., a one million increase in the audience for violent movies reduces violent crime by 1.1% to 1.3%. After exposure to the movie, between 12 a.m. and 6 a.m., violent crime is reduced by an even larger percent. This finding is explained by the self-selection of violent individuals into violent movie attendance, leading to a substitution away from more volatile activities. In particular, movie attendance appears to reduce alcohol consumption. The results emphasize that media exposure affects behavior not only via content, but also because it changes time spent in alternative activities. The substitution away from more dangerous activities in the field can explain the differences with the laboratory findings. Our estimates suggest that in the short run, violent movies deter almost 1,000 assaults on an average weekend. Although our design does not allow us to estimate long-run effects, we find no evidence of medium-run effects up to three weeks after initial exposure.

This paper examines whether the salience of a tax system affects equilibrium tax rates. I analyze how tolls change after toll facilities adopt electronic toll collection (ETC); drivers are substantially less aware of tolls paid electronically. I estimate that, in steady state, tolls are 20 to 40 percent higher than they would have been without ETC. Consistent with a salience-based explanation for this toll increase, I find that under ETC, driving becomes less elastic with respect to the toll and toll setting becomes less sensitive to the electoral calendar. Alternative explanations appear unlikely to be able to explain the findings.

This paper presents a randomized field experiment on community-based monitoring of public primary health care providers in Uganda. Through two rounds of village meetings, localized nongovernmental organizations encouraged communities to be more involved with the state of health service provision and strengthened their capacity to hold their local health providers to account for performance. A year after the intervention, treatment communities are more involved in monitoring the provider, and the health workers appear to exert higher effort to serve the community. We document large increases in utilization and improved health outcomes—reduced child mortality and increased child weight—that compare favorably to some of the more successful community-based intervention trials reported in the medical literature.

This paper challenges the view that the wage structure in West-Germany has remained stable throughout the 80s and 90s. Based on a 2 % sample of social security records, we show that wage inequality has increased in the 1980s, but only at the top of the distribution. In the early 1990s, wage inequality started to rise also at the bottom of the distribution. Hence, while the US and Germany experienced similar changes at the top of the distribution throughout the 80s and 90s, the patterns at the bottom of the distribution are reversed. We show that changes in the education and age structure can explain a substantial part of the increase in inequality, in particular at the top of the distribution. We further argue that selection into unemployment cannot account for the stable wage structure at the bottom in the 80s. In contrast, about one third of the increase in lower tail inequality in the 90s can be related to de-unionization. Finally, fluctuations in relative supply play an important role in explaining trends in the skill premium. These findings are consistent with the view that technological change is responsible for the widening of the wage distribution at the top. The widening of the wage distribution at the bottom, however, may be better explained by episodic events, such as changes in labour market institutions and supply shocks.

Cable and satellite television have spread rapidly throughout the developing world. These media sources expose viewers to new information about the outside world and other ways of life, which may affect attitudes and behaviors. This paper explores the effect of the introduction of cable television on women's status in rural India. Using a three-year, individual-level panel data set, we find that the introduction of cable television is associated with significant decreases in the reported acceptability of domestic violence toward women and son preference, as well as increases in women's autonomy and decreases in fertility. We also find suggestive evidence that exposure to cable increases school enrollment for younger children, perhaps through increased participation of women in household decision making. We argue that the results are not driven by preexisting differential trends.

We study two parties who desire a smooth trading relationship under conditions of value and cost uncertainty. A contract fixing price works well in normal times because there is nothing to argue about. However, when value or cost is unusually high or low, one party will deviate from the contract and hold up the other party, causing deadweight losses as parties withhold cooperation. We show that allocating asset ownership and indexing contracts can reduce the incentives to engage in hold-up. In contrast to much of the literature, the driving force in our model is payoff uncertainty, rather than noncontractible investments.