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. 相似文献
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. 相似文献
We use a vertical product differentiation model under partial market coverage to study the social welfare optimum and duopoly equilibrium when convex costs of quality provision are either fixed or variable in terms of production. We show the following new results. First, under fixed costs, the social planner charges a uniform price for the single variant that just covers costs of quality provision. Like the duopoly equilibrium, this socially optimal pricing entails a partially uncovered market, but a smaller share of the market is served compared with the duopoly equilibrium. Second, for the variable cost case, it is socially optimal to provide both high‐ and low‐quality variants, but market shares need not be equal. This differs from the result in fully covered markets. Third, in the duopoly equilibrium, the quality spread is too wide under variable costs relative to the social optimum. Under fixed costs, the duopoly produces two variants, but quality is too low relative to the social optimum, which has only one variant. 相似文献
The South African research community which undertakes all research activity in the social and natural sciences, with and without state and corporate sponsorship, draws its membership mainly from the dominant social group. In this country, the dominant group is both economically and racially determined. Consequently, the white minority dominates the research community and intellectual discourse as it does other socio‐economic and political spheres of society. This situation guarantees the constant reproduction and perpetuation of the social relations of racial domination.
As an agent that generates knowledge and new ideas, research as an academic and intellectual tool of enquiry is an instrument of social control, producing new concepts, language and theoretical abstractions which are not accessible to those outside its multi‐farious disciplines. Insofar as the largest proportion of practitioners of these specialised disciplines is drawn from the dominant group, research has itself become a pivotal part of the dominant ideology. Its role is inevitably and inextricably bound up with the processes of systematic reproduction of the relations of domination.
The aim of this viewpoint is therefore to explore various ways in which research bodies and intellectual discourse in general in South Africa can be deracialised and be made more representative of the social make‐up of society. 相似文献
Many more than ever face the crises of childhood: violence, drugs, bad schools, poverty, divorce, or two parents at work. And no one seems to care. 相似文献
Summary This paper considers the relationship between economic size and vulnerability to external disturbances. In order to analyze this issue effectively a model comprising three different-sized economies is constructed. The issue of economic size and insulation is approached from this alternative perspectives depending upon the relative size of (a) the `recipient' country and (b) the transmitting country. The results of the analysis indicate that, contrary to popular belief, a small country under floating exchange rates is less severely affected by external economic events than a large economy regardless of the type of external disturbance and the degree of domestic wage indexation.This paper has been improved by the helpful comments of a referee. We alone are solely responsible for all remaining errors. 相似文献
Consumer susceptibility to reference group influence has been demonstrated for certain products and buying situations. This
article reports a study designed to determine if reference group influence varies between consumers classified as situationally-oriented
and dispositionally-oriented. Results indicate a considerable difference between the two groups.
Independence Health Plan 相似文献