RECENT research on employment discrimination against blacks and women suggests that no single determinant education, location, growth, or others is primary. Yet the belief persists (see Alchian and Kessel, 1962; Arrow, 1971; Ashenfeiter, 1969; Becker, 1957; Bergmann, 1971; Comanor, 1971; Shepherd, 1969; Thurow, 1969) that the employers' power to choose may be important, via their managerial preferences and discretionary resources. These influences would be visible in large industrial firms which possess market power. In this paper we test whether the industrial structure and performance of large firms have in fact been related to their employment of blacks and women. The analysis covers about 200 of the largest United States industrial enterprises, using employment data for 1966 and 1970. The focus is on white-collar employment patterns. Being more directly subject to upper management control than is blue-collar employment, the white-collar patterns may provide a sensitive test of whatever role is played by enterprise policy under varying conditions and constraints. First we discuss the basic hypotheses to be tested in section I. Section II explains the variables and the basic models which are to be analyzed. Section III presents the empirical results. And finally, the findings are summarized in section IV.

The relationship between age and the publishing productivity of Ph.D. scientists is analyzed using data from the Survey of Doctorate Recipients (National Research Council) and the Science Citation Index. The longitudinal nature of the data allows for the identification of pure aging effects. In five of the six areas studied, life-cycle aging effects are present. Only in particle physics, where scientists often speak of being on a "religious quest," is there indication that scientific productivity is not investment-motivated. Vintage effects are also considered. The expectation that the latest educated are the most productive is not generally supported by the data.

Sharon G. Levin, Stanford L. Levin, John B. Meisel, Market Structure, Uncertainty, and Intrafirm Diffusion: The Case of Optical Scanners in Grocery Stores, The Review of Economics and Statistics, Vol. 74, No. 2 (May, 1992), pp. 345-350

Two p roportional hazard models are used to investigate the differingeffects of marke t structure variables on the conditional probabilityof a firm initially adoptin g the new technology of optical scanners as the innovation spreads through the f ood store industry. During the early stage, leading firms with large average sto re size which are not members of chains and which operate in less concentrated m arkets with higher incomes and wage rates, tend to adopt scanners sooner. Later on, differences in seller concentration, market share, and size become less impo rtant as other firms follow prior adoptions. Copyright 1987 by MIT Press.

The relationship between age and the publishing productivity of Ph.D. scientists is analyzed using data from the Survey of Doctorate Recipients (National Research Council) and the Science Citation Index. The longitudinal nature of the data allows for the identification of pure aging effects. In five of the six areas studied, life-cycle aging effects are present. Only in particle physics, where scientists often speak of being on a "religious quest, " is the indication that scientific productivity is not investment-motivated. Vintage effects are also considered. The expectation that the latest educated are the most productive is not generally supported by the data. Copyright 1991 by American Economic Association.