This paper examines the impact of de jure desegregation on education in the South and of increased black voting power on the demand for black schoolteachers in the United States. Because changes in the black share of voters in the post-World War II South are due largely to "exogenous" national laws (the Voting Rights Act of 1965, in particular), the paper provides a unique test of the impact of changes in political power on public decision making. The main finding is that increased black voting power appears to have raised demand for black school-teachers in the 1960s. There is additional suggestive evidence that black voting power operated in part through election of black officials. The increase in demand due to the changes in voting offset most of the reduction in demand due to desegregation of schooling in the South, averting the potential dire effects of desegregated education on employment of black teachers. Instead of declining, relative employment of blacks in teaching was maintained, and relative incomes rose in the 1950s and 1960s. These results are consistent with broad "governmental discrimination" hypothesis that much of the economic progress or retrogression of blacks in the United States is explicable in terms of black political power and resultant governmental activity.

By examining the ethnic identity of authors in over 2.5 million scientific papers written by US-based authors from 1985 to 2008, we find that persons of similar ethnicity coauthor together more frequently than predicted by their proportion among authors. The greater homophily is associated with publication in lower-impact journals and with fewer citations. Meanwhile, papers with authors in more locations and with longer reference lists get published in higher-impact journals and receive more citations. These findings suggest that diversity in inputs by author ethnicity, location, and references leads to greater contributions to science as measured by impact factors and citations.

THE ease of substitution between labor and other factors of production is an important determinant of the elasticity of demand for labor and thus of the economic effects of unionism. All else the same, the greater the elasticity of substitution, the greater is the elasticity of derived demand and the greater the displacement of labor for a given union-induced wage increase. In sectors where this elasticity is large, unions are likely to be relatively weak and able to win only slight wage gains (Freeman and Medoff, 1981 and forthcoming) or, if they win large gains, will have to pay a high price in terms of lost jobs. In the sectors where the elasticity is small, unions may be able to extract a substantial wage premium at little cost in terms of employment. Moreover, as a simple general equilibrium model indicates, the elasticity of substitution between labor and other factors in the unionized sector is a key parameter in determining the impact of the IIunion wage effect on the earnings of nonunion workers and on the efficiency of the economy (Johnson and Mieskowski, 1970). Despite the importance of the elasticity of labor demand for an analysis of unionism, little attention has been given to the absolute and magnitude of this elasticity under collective bargaining. While there is some discussion of technological change and the substitution of capital and nonproduction workers for organized production workers in the institutional literature (e.g., Slichter, 1941; Slichter, Healy and Livernash, 1960; Bok and Dunlop, 1970), modern econometric work provides no estimates of the relevant parameters. As a result, Johnson and Mieskowski (1970), Rees (1963), Lewis (1964) and others have been forced to evaluate union effects with guesstimates of the elasticities of concern in union settings. This paper attempts to fill some of the gap in our knowledge by providing estimates for U.S. manufacturing of the constant output elasticity of demand for unionized and nonunionized production workers and of the elasticity of substitution between these workers and other inputs. The analysis concentrates on what we call the relative inelasticity hypothesis, which states that the demand for production workers will be more inelastic in the presence of a union for two reasons: the likelihood that unions have organized and survived in sectors with low elasticities, and the effects of various contract provisions on the ability of management to substitute other factors for production labor. The study is divided into four sections. Section I develops the rationale for the inelasticity hypothesis and describes the nature of the empirical analysis conducted to test its validity. The second section uses a 1972 state by 2-digit Standard Industrial Classification (SIC) industry data file for manufacturing to estimate the elasticity of substitution between production labor and both nonproduction labor and capital in the union and nonunion sectors of U.S. manufacturing industries. Section III provides estimates, based on a 1968-72 sample of manufacturing establishments, of the elasticity of substitution between production and nonproduction labor (the only two inputs for which information is available). The final section briefly summarizes the findings and discusses their implications for understanding the impact of trade unionism on the U.S. economy. To preview the ensuing discussion, our main conclusion is: Substitution between production labor and other inputs is generally lower in union Received for publication March 6, 1978. Revision accepted for publication August 17, 1981. * Both authors are with Harvard University and the National Bureau of Economic Research. Supported by U.S. Department of Labor Grant No. J-9-M-6-0094, National Science Foundation Grant No. APT77-16279, and the National Bureau of Economic Research (under its program of research on labor economics). We are especially grateful to Jane Mather for her invaluable assistance on this project and to Greg Bialecki, Charles Brown, Gary Chamberlain, Kathy Coons, Jon Fay, Martin Van Denburgh, and Lori Wilson for their significant contributions. The study has not been reviewed by the Board of Directors of the National Bureau.

T HE impact of unions on wages is likely to depend on the extent to which they organize workers in the relevant product market.1 As the organization in a market increases, the opportunity for substituting nonunion for union products will be reduced, lowering the elasticity of demand for organized workers and the potential loss of employment for a given wage increase. As a result, the wages of union workers are likely to be higher, all else the same, the greater the percentage organized. The wages of nonunion workers may also be influenced by the extent of organization, though the direction of the effect is not clear. On the one hand, union wage gains due to greater coverage may induce increases in nonunion wages because of the threat of organization and/or because of shifts in demand favoring nonunion producers brought about by the increased relative cost of union labor. On the other hand, the supply of labor to nonunion firms may increase as a result of reduced employment in the union sector, which would most likely depress nonunion wages. Whether the threat plus demand effect or the supply effect dominates is an empirical issue. The impact of the percentage organized on the union wage differential (the difference between the natural logarithms of union and of nonunion wages) depends on the relative magnitudes of the likely positive impact on union wages and the positive or negative impact on nonunion wages. This paper seeks to disentangle the relation between the percentage of workers organized in a product market and the wages received by union workers and by nonunion workers. In contrast to most of the literature on the union wage effect, which either relates some average of wages in an industry to the percentage organized or which relates the wages of individuals to their membership in a union, our analysis examines the impact of the percentage organized on the compensation of union labor and nonunion labor taken separately.2 By relating the wages of unionized workers to the percentage covered by collective bargaining in the relevant product market, we estimate directly the extent to which unionized workers in highly organized markets receive higher wages than unionized workers in less organized settings. By relating nonunion wages to the percentage covered, we provide direct estimates of the extent to which, as a result of threat, demand, and supply effects, nonunion workers in highly organized markets receive higher or lower wages than nonunion workers in less organized industries or areas. Two sets of data are used in the study: information on individuals from the 1973, 1974, and 1975 May Current Population Surveys (CPS), which contain data on usual weekly earnings, usual weekly hours, union membership status, and key personal characteristics; and information on establishments from the Bureau of Labor Statistics' 1968, 1970, and 1972 Expenditures for Employee Compensation Surveys (EEC), which contain data on the components of compensation, labor hours, collective bargaining coverage, and some relevant establishment characteristics. The availability of both individual and establishReceived for publication April 24, 1980. Revision accepted for publication May 27, 1981. * Harvard University. We have benefited from the comments of K. Abraham, C. Brown, H. G. Lewis, and L. Summers. We are most grateful to G. Bialecki, J. Fay, C. Ichniowski, L. Nelson, M. Van Denburgh, L. Wilson, and J. Zax for research assistance. The study has been supported by the National Science Foundation (Grant APR 77-16279) and the National Bureau of Economic Research (under its program for research on labor economics). Any opinions expressed are not necessarily shared by the individuals who have aided us, NSF, or NBER. I Throughout our theoretical discussion we refer to a product market, which is the appropriate unit of observation for an analysis of the relationship between percentage organized and wages. However, in the empirical work we focus on either a 3-digit Standard Industrial Classification or Census industry (in the manufacturing analysis) or a Current Population Survey state group (in the construction analysis). Unfortunately, the data used do not permit a closer correspondence between the theoretical and empirical parts of our study. 2 For an early attempt to disentangle this relation, using average wages in an industry and percentage organized, see Rosen (1969). For more recent related analyses, see (in alphabetical order) Donsimoni (1978), Hendricks (1975), Kahn (1978), and Lee (1978). For a trenchant treatment of the analysis, see Lewis (1980).

This study investigates the impact of union organization on the wages and labor practices of establishments newly organized in the 1980s. It uses a research design in which establishments are "paired" with their closest nonunion competitor. It finds that, unionism had only a modest effect on wages in the newly organized plants, which contrasts sharply with the huge union wage impact found in cross-section comparisons of union and nonunion individuals, but unionism substantially alters several personnel practices, creating grievance systems, greater seniority protection, and job bidding and posting. That newly organized establishments adopt union working conditions but grant only modest wage increases suggests that "collective voice" rather than monopoly wage gains is the key to understanding new unionism.