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.     

Measurement of English farming technological change, 1523–1900

I have argued that for the period from 1661 to 1850, patent data in England were consistent in that no official changes in methods and standards of issuance occurred. Book data on titles published on farming production methods were similarly consistent from 1523 to the mid-19th century because the market for books developed gradually and the technology of printing was not substantially changed until the mid-19th century.My main point is that data on output of titles of books on farming productive techniques in England are useful measures of technological change. Books did have information on good production methods and could express productive ideas where a patent may not be issued. Further, the literacy rate of farmers was high so that books were likely an important source of ideas on farming production methods. Finally, the fluctuations in the book data were highly related to the fluctuations in the patent data, suggesting that a common set of factors caused those fluctuations. The high correlations between the detrended book and patent data indicate that if we accept patenting as a useful measure of technology we may also accept book title output of a technical nature as a good measure of technical change.I used the data for a simple analysis of the trend growth rate of agricultural technology in England from 1551 to 1850. While there is limited evidence to show that the subperiod 1651–1750 saw a slowing in the trend of development of farming technology, I argue that a division of the entire period into subperiods is too simplistic. A more fruitful approach would be an analysis of the underlying forces that determined the trend of development of the technology of English agriculture.The next step is an analysis of the forces that influenced technological development of English farming. From an economic point of view, market forces play an important role in influencing technology. Because such an analysis deserves careful consideration, I leave that to another paper (see Sullivan and Simon, 1983).     

中国和美国正在走向冲突?

随着中国的崛起,中国和世界上唯一的超级大国美国之间的国力差距在缩小。不少观察家担心,武装冲突将随之发生。在近代历史上,出现过七次大国崛起,挑战现存强国,其中六次都导致了冲突。但是,本文指出,有理由相信,中国的崛起将是和平的。     

Current Agricultural Situation Calls for Science and Technology

The first document,or known as the No.1 document,to address China's agricultural issue by improving agriculture science and technology is in urgent need,considering the present situation facing the agricultural development.