Knowledge that Transforms

This paper provides empirical evidence about the effect of unearned income on earnings, consumption, and savings. Using an original survey of people playing the lottery in Massachusetts in the mid-1980's, we analyze the effects of the magnitude of lottery prizes on economic behavior. The critical assumption is that among lottery winners the magnitude of the prize is randomly assigned. We find that unearned income reduces labor earnings, with a marginal propensity to consume leisure of approximately 11 percent, with larger effects for individuals between 55 and 65 years old. After receiving about half their prize, individuals saved about 16 percent.

Advances in Routing Technologies and Internet Peering Agreements by Stanley Besen, Paul Milgrom, Bridger Mitchell and Padmanabhan Srinagesh. Published in volume 91, issue 2, pages 292-296 of American Economic Review, May 2001

This paper examines the magnitude of informational problems associated with the implementation and interpretation of simple monetary policy rules. Using Taylor's rule as an example, I demonstrate that real-time policy recommendations differ considerably from those obtained with ex post revised data. Further, estimated policy reaction functions based on ex post revised data provide misleading descriptions of historical policy and obscure the behavior suggested by information available to the Federal Reserve in real time. These results indicate that reliance on the information actually available to policy makers in real time is essential for the analysis of monetary policy rules.

Futures exchanges and other financial intermediaries assume counterparty risks and demand in return guarantees that these counterparties will deliver on their promises. It is often argued that to attract volume, financial intermediaries would settle for excessively low contractual guarantees. In Tano Santos and José Scheinkman (2001) we model financial intermediation in an environment where traders may choose to default, and we examine the characteristics of the equilibrium. In particular, we investigate whether competition implies excessively low standards. We show that in fact, when society punishes default and intermediaries can impose collateral requirements to effectively limit the size of positions, competition leads to a (constrained) optimal amount of contractual guarantees. In Santos and Scheinkman (2001) we assume that exchanges cannot control the size of the positions taken by individuals, but we preclude investors from participating in more than one exchange. This ignores the effect that trading with one financial intermediary may have on the risks faced by other intermediaries. Financial intermediaries typically cannot control the amount of risk that counterparties will take with other intermediaries. In this paper we examine the effect of dropping this exclusivity assumption. We show that the constrained optimum can no longer be implemented as a standard Nash equilibrium with free entry. Nonetheless this allocation is the only one that can be sustained as an anticipatory equilibrium (Charles Wilson (1977)). To break a candidate anticipatory

Used properly, the term 'new e-conomy' is warranted. Since 1995, there has been a wave of innovation associated with both the production and use of information technology that has been translated into improved US economic performance. In particular, there has been a substantial acceleration in trend total factor productivity growth. Most of this acceleration actually took place outside of the computer sector. Almost none of the acceleration was cyclical. There is now clear supportive evidence of an acceleration of productivity in service industries that are major purchasers of information technology such as finance and wholesale and retail trade. These gains reflect not only increased investment in information technology but also complementary innovations in business organization and policy. To be sure, as evidenced by recent financial market volatility, there have been speculative excesses, but these should not obscure the fundamental gains that have been made.

Employment relationships typically involve the division of surplus. Surplus can be the result of a good match, a monopoly rent, or a quasirent that arises because of a specific investment. The division of this surplus is of economic interest as it is a determinant of turnover, investment, and wages. Gary S. Becker (1962) argued, in the context of specific human-capital investments, that the incumbent employee and firm will share the surplus. This notion was formalized in a prototypical model of surplus sharing as first proposed by Masanori Hashimoto (1981). The model has been studied extensively, among others by H. Lorne Carmichael (1983), Robert E. Hall and Edward P. Lazear (1984), and Donald O. Parsons (1986), while Elizabeth Becker and Cotton M. Lindsay (1994) provide an empirical application. The key feature of the model is the existence of transaction costs. Both the employee and the firm have (ex ante uncertain) private information on which they cannot write a contingent contract. This makes that they write a nonrenegotiable contract that specifies a fixed wage. After this, the firm learns the value of the employee’s marginal product whereas the employee learns the value of his outside option. Both parties then decide unilaterally whether to separate or not and inefficient separations may occur. The wage is set in such a way as to maximize the expected total surplus. The present analysis will consider the role of uncertainty in this model. This has not been done before in a rigorous way. Hashimoto considered only degenerate cases. His analysis suggests that the wage will be low when the uncertainty of the market conditions is small, and high when the uncertainty of the conditions inside the firm is small. Parsons (1986) makes a claim that this is actually the case without deriving the result. This paper shows that the comparative statics are ambiguous and may well be the opposite of those suggested by Hashimoto and claimed by Parsons. It also provides the intuition that is behind this result, namely that uncertainty not only influences turnover but also the option value of the match and its opportunity cost. Section I, briefly summarizes Hashimoto’s model and shows that without further assumptions the comparative statics are ambiguous. Section II derives an explicit solution of the wage. Section III briefly considers alternative wage-setting schemes and Section IV concludes.

Propensity-score matching is a nonexperimental method for estimating the average effect of social programs (see William Cochran, 1968; Paul Rosenbaum and Donald Rubin, 1983; James Heckman et al., 1998b). The method compares average outcomes of participants and nonparticipants, conditioning on the propensityscore value. The average comparison measures the average impact of a program. This methodology has received much attention recently in econometrics (see Heckman et al., 1996, 1997, 1998a, b; Jinyong Hahn, 1998; Rajeev Dehejia and Sadek Wahba, 1999; Jeffrey Smith and Petra Todd, 2000; Keisuke Hirano et al., 2000). The underlying identification requirement of the matching methodology is that the program choice is independent of outcomes conditional on a certain set of observables. While intuitively attractive in that the method replicates features of randomized experiments within observational data, the identification requirement excludes a possibility that the program-choice decision could be correlated with the outcomes given the set of observables (see Heckman et al., 1997, 1998b). Unobservables that are correlated both with an outcome and the program choice are not allowed. There are some efforts to estimate more general models using nonparametric methods (see Whitney Newey and James Powell, 1989; Heckman, 1997; Alberto Abadie, 2000; Serge Darolles et al., 2000; Matali Das, 2000; JeanPierre Florens, 2000; Ichimura and Taber, 2000). One such effort is the use of the instrumental-variable methods. Heckman (1997) has shown that the set of assumptions to justify instrumental-variable methods are very restrictive from the perspective of behavioral models of program participation. We show that his conditions justifying instrumental-variable methods actually justify the matching method as a special case.1 This observation ties the limitations of the matching method in line with those of instrumental-variable methods and also is useful in constructing specification tests for matching methods when valid instrumental variables are available. This is analogous to testing the validity of the identification conditions for ordinary least-squares (OLS) estimators when there are overidentifying instrumental variables. We then present two different propensityscore methods that are based on instrumental variables. Both methods include standard propensity-score matching as special cases. They help reduce the dimension of the conditioning variables without invoking functional-form assumptions in the same way that the standard propensity-score matching helps reduce the dimension of the conditioning variables. We show how to use these ideas to construct estimators that can be easily implemented.

The resurgence of the American economy since 1995 has outrun all but the most optimistic expectations. Economic forecasting models have been seriously off track and growth projections have been revised to reflect a more sanguine outlook only recently. It is not surprising that the unusual combination of more rapid growth and slower inflation in the 1990's has touched off a strenuous debate among economists about whether improvements in America's economic performance can be sustained. The starting point for the economic debate is the thesis that the 1990's are a mirror image of the 1970's, when an unfavorable series of supply shocks led to stagflation -- slower growth and higher inflation. In this view, the development of information technology (IT) is one of a series of positive, but temporary, shocks. The competing perspective is that IT has produced a fundamental change in the U.S. economy, leading to a permanent improvement in growth prospects.

This paper examines the risk aspects of an investment-based defined contribution Social Security plan. We focus on the risk after the plan is fully phased in. Individuals deposit a fraction of wages to a Personal Retirement Account (PRA), invest these funds in a 60:40 equity-debt mix, and in a similarly invested annuity at age 67. The value of the assets follows a random walk with mean and variance of a 60:40 equity-debt portfolio over the period 1946-95, a mean log return of 5.5 percent (net of administrative costs of 0.4 percent) and a standard deviation of 12.5 percent. We study he stochastic distributions of this process by doing 10, 000 simulations of the 80-year experience of the cohort that reached age 21 in 1998. The resulting annuities are compared to the future defined benefits specified in current law (the benchmark' benefits). With no uncertainty, a 5.5 percent log return would permit the benchmark benefits to be purchased with PRA deposits of 3.1 percent of payroll, only one-sixth of the pay-as-you-go tax needed for the benchmark benefits. Saving a higher share of wages provides a cushion' that protects the individual from the risk of an unacceptably low level of benefits. For example, PRA deposits of 6 percent of wages reduces the probability that the benefits are less than the benchmark to 0.17 and the probability that they are less than 61 percent of the benchmark to 0.05. PRA deposits of 9 percent of wages (half of the tax rate required in a pay-as-you-go system) would substantially reduce these risks. This pure investment-based plan is an extreme case. The investment risk can be reduced further by using a mixed system that combines pay-as-you-go and investment-based components or that makes intergenerational transfers conditional on the performance of stock and bond prices.

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