The Robustness of the APT to Alternative Estimators

We test the robustness of the APT to two alternative estimation procedures: the Fama and MacBeth (1973) two-step methodology; and the one-step procedure due to Burmeister and McElroy (1988). We find that the APT is indeed sensitive to the chosen estimator and assumptions about the factor structure of stock returns. We believe that our findings have implications for the estimation of asset pricing models in general.     

THE RETURNS TO ENDOGENOUS HUMAN CAPITAL IN PAKISTAN'S RURAL WAGE LABOUR MARKET

This paper estimates the private returns to human capital in Pakistani rural labour markets. The rich data used permit inclusion of several dimensions of human capital and control for endogeneity resulting from investment in human capital. The results suggest that, without data on determinants of human capital, it would not be possible to disentangle the separate effect of each dimension of human capital on wage differentials nor to distinguish human capital explanations for wage differentials from signalling and credentialist models. With control for endogeneity of human capital and selectivity into wage employment, cognitive achievement, but not schooling attainment separate from cognitive achievement nor long-run health status, affects wage differentials.     

Position limits for cash‐settled derivative contracts

Cash settlement of derivative contracts makes them susceptible to manipulation by traders who expect to close large positions upon final settlement. Cash settlement also increases underlying volatility when hedgers unwind their hedges if they have no incentives to control their trading costs. Limits on the positions that traders can carry into final settlement can be used to mitigate associated economic inefficiencies when surveillance is insufficient. This article develops a model that regulators can use to set these limits that is based upon microstructure theory. The empirical findings indicate that existing position limits are largely inconsistent with those suggested by the model. © 2005 Wiley Periodicals, Inc. Jrl Fut Mark 25:945–965, 2005     

Projecting the future size and health status of the U.S. elderly population

"A projection model based on a multivariate continuous state, stochastic process is presented. The model allows multiple time-varying covariates to be used so parameters can be estimated from time series information on health changes and mortality, and their interaction. Health changes are simulated by altering parameters controlling the age trajectory and diffusion of risk factor means, variances, and covariances....By increasing the information used in projections it may be possible to better (a) anticipate the state of health at extreme ages, (b) forecast changes in health at specific ages over time, (c) stimulate the effects of specific interventions, and (d) determine the sensitivity of outcomes to a range of interventions."     

RECEIPT OF INFORMATION AND INFLUENCE OVER DECISIONS IN HOSPITALS BY THE BOARD, CHIEF EXECUTIVE OFFICER AND MEDICAL STAFF

This article examines relationships between receipt of internal administrative information in hospitals, influence over general management decisions, and the extent to which certain organizational characteristics predict the receipt of information by each of the three major groups in hospitals: the board, the CEO, and the medical staff. Using a US national sample of 287 non-profit community hospitals, CEOs were found to receive the greatest amount of information and had highest influence while medical staffs were lowest on both measures. of five major organizational characteristics, hospital size emerged as the single strongest predictor of receipt of information for both boards (beta =?0.28, p 0.001) and medical staffs (beta =?0.42, p 0.001). Overall, the five dependent variables explained 18 per cent of the variance in receipt of information by boards and 28 percent of the variance for medical staffs.