The Returns to Academic and Vocational Qualifications in Britain

This paper uses data from the 1991 sweep of the National Child Development Study (NCDS) and the 1998 Labour Force Survey (LFS) to provide a comprehensive analysis of the labour market returns to academic and vocational qualifications. The results show that the wage premia from academic qualifications are typically higher than from vocational qualifications. However, this gap is reduced somewhat, when we control for the amount of time taken to acquire different qualifications. This is particularly important for vocational courses, which generally take shorter time periods to complete. In the paper we also investigate how returns vary by gender, subsequent qualifications, and the natural ability of individuals. Finally, by comparing the NCDS results with those from the LFS, we estimate the bias that can result from not controlling for factors such as ability, family background and measurement error. The results reveal that the estimated returns in the NCDS equations controlling for ability, family background and measurement error are similar to the simple OLS estimates obtained with the LFS, which do not control for these factors. This suggests that the biases generally offset one another.     

Public Sector Capital and the Production Efficiency of U.S. Regional Manufacturing Industries

This paper applies a stochastic frontier production model with time-varying technical efficiency to investigate the relationship between public capital and technical efficiency. It is based on the proposition that public capital has an effect on actual output by enhancing technical efficiency, thereby reducing the gap between maximum potential output and actual output. Empirical results using panel data from U.S. state manufacturing industries during 1969–86 show that technical efficiencies varied substantially, both between states and between years; variations in technical efficiency are significantly explained by variations in public-sector capital.
JEL Classification Numbers: O20, H54, C23.     

Heterogeneity and Share Contracting in Medical Group Practices

This paper offers an empirical analysis of the relationship between income sharing rules and physician heterogeneity in medical group practices.The economies to group formation associated with risk–sharing, mutual monitoring,and internal referral are served by sharing at least a portion of group income equally. Sharing group income equally is problematic, however, when group members differ in their contribution to group income. Member contributions to group income may differ because of differences in ability, effort, or the price of services across specialty fields. The analysis below is addressed to the question of how income sharing rules in physician groups are affected by variation in member contributions. The analysis finds evidence that heterogeneity in member contributions to group income limits the use of equal income sharing rules in multispecialty groups relative to single specialty groups, and large groups relative to small groups. Nevertheless, 65% of all groups in the survey share at least a pn of group income equally, which broadly suggests that the joint surplus enhancement from risk sharing, mutual monitoring, and internal referral are sufficient to overcome the incentive problems of such rules     

Multiple regimes and cross-country growth behaviour

This paper provides some new evidence on the behaviour of cross-country growth rates. We reject the linear model commonly used to study cross-country growth behaviour in favour of a multiple regime alternative in which different economies obey different linear models when grouped according to initial conditions. Further, the marginal product of capital is shown to vary with the level of economic development. These results are consistent with growth models which exhibit multiple steady states. Our results call into question inferences that have been made in favour of the convergence hypothesis and further suggest that the explanatory power of the Solow growth model may be enhanced with a theory of aggregate production function differences.     

Foodcrop Demand in Indonesia: A Systems Approach

Aggregate agricultural commodity demand parameters are estimated, based on an application of the Deaton and Muellbauer Almost Ideal Demand System to a seventeen year Indonesian time-series data set of prices, expenditures and consumption availability. The statistical results are generally significant and correctly signed. The revealed demand relationships imply that the Indonesian food Staples are normal goods. Expenditure elasticities are higher for the higher value foodstuffs than for the lower value starchy staples. Furthermore, the demand for rice has become highly inelastic to both own and cross-price interventions. This implies that rice price interventions will require a high degree of fine-tuning in order to stabilise prices effectively, and that low urban rice prices cannot be regarded as an appropriate, or even second best policy instrument for improving nutritional status.

A high degree of Substitution between rice and secondary food crops, and amongst groups of secondary food crops, is identified. The significance of the cross-price elasticities for the secondary food crops suggests that single-market interventions will have non-trivial budget-mediated effects in other commodity markets. The management of a multi-commodity food policy requires that the spillover effects from commodity pricing policy must be taken into account in order to optimise the effects of price policy interventions.     

Educational attainment and cohort size

"We argue that the postwar baby boom [in the United States] caused substantial fluctuations in both the economic rewards to education and educational attainment over the last 3 decades. If substitutability between young and old workers diminishes with education, the present value of lifetime earnings for a boom cohort is depressed more for highly educated workers, reducing incentives for educational attainment. The opposite is true for pre- and postboom cohorts. The diminishing substitutability hypothesis explains the declines in both the returns to college and college completion rates in the 1970s and predicts a substantial increase in educational attainment for postboomers."     

Small firm mutual funds: Additional evidence on the small firm effect

Returns generated with small firm mutual fund data are used to examine the extent to which identification of a small firm effect is due to the difficulty in measuring the direct and indirect transaction costs involved in investing in the common shares of small capitalization stocks. Little if any evidence of the excess risk-adjusted returns is obtained for either of the period 1978–1983, when the small firm effect was observed, or the period 1984–1989, when it was not. The small firm effect may therefore be attributed to (1) higher direct transaction costs including bid-ask spread and broker fees and (2) higher indirect transaction costs including portfolio management expenses and market impact costs.The authors thank an anonymous referee for helpful comments on an earlier version of this paper, and Brett Salazar for valuable assistance in data collection. Errors remain our own.     

Lower Bound Restrictions on Intensities in Data Envelopment Analysis

We propose an extension to the basic DEA models that guarantees that if an intensity is positive then it must be at least as large as a pre-defined lower bound. This requirement adds an integer programming constraint known within Operations Research as a Fixed-Charge (FC) type of constraint. Accordingly, we term the new model DEA_FC. The proposed model lies between the DEA models that allow units to be scaled arbitrarily low, and the Free Disposal Hull model that allows no scaling. We analyze 18 datasets from the literature to demonstrate that sufficiently low intensities—those for which the scaled Decision-Making Unit (DMU) has inputs and outputs that lie below the minimum values observed—are pervasive, and that the new model ensures fairer comparisons without sacrificing the required discriminating power. We explain why the low-intensity phenomenon exists. In sharp contrast to standard DEA models we demonstrate via examples that an inefficient DMU may play a pivotal role in determining the technology. We also propose a goal programming model that determines how deviations from the lower bounds affect efficiency, which we term the trade-off between the deviation gap and the efficiency gap.