We use a unique new data set that combines individual worker data with data on workers' employers to estimate plant-level production functions and wage equations, and thus to compare relative marginal products and relative wages for various groups of workers. The data and empirical framework lead to new evidence on numerous questions regarding the determination of wages, questions that hinge on the relationship between wages and marginal products of workers in different demographic groups. These include race and sex discrimination in wages, the causes of rising wages over the life cycle, and the returns to marriage. First, workers who have ever been married are more productive than never-married workers and are paid accordingly.Second, prime-aged workers (aged 35-54) are equally as productive as younger workers, and in some specifications are estimated to receive higher wages. However, older workers (aged 55+) are less productive than younger workers but are paid more. Third, the data indicate no difference between the relative wage and relative productivity of black workers.Finally, with the exception of managerial and professional occupations, women are paid about 25-35% less than men, but estimated productivity differentials for women are generally no larger than 1570, and significantly smaller than the pay differential.

We assemble a new matched employer-employee data set covering essentially all industries and occupations across all regions of the U.S. We use this data set to re-examine the question of the relative contributions to the overall sex gap in wages of sex segregation vs. wage differences by sex within occupation, industry, establishment, and occupation-establishment cells. This new data set is especially useful because earlier research on this topic relied on data sets that covered only a narrow range of industries, occupations, or regions. Our results indicate that a sizable fraction of the sex gap in wages is accounted for by the segregation of women into lower-paying occupations, industries, establishments, and occupations within establishments. Nonetheless, a substantial part of the sex gap in wages remains attributable to the individual's sex. This latter finding contrasts sharply with the conclusions of previous research (especially Groshen, 1991), which indicated that sex segregation accounted for essentially all of the sex wage gap. Further research into the sources of withinestablishment within-occupation sex wage differences is therefore much more important than previously thought.

I examine the importance of physicians in the process by which patients receive either trade-name or generic drugs. Using a dataset on physicians, their patients, and the multisource drugs prescribed, I find that almost all physicians prescribe both types of drugs to their patients, but some physicians are more likely to prescribe generic drugs while other physicians are more likely to prescribe trade-name drugs. Very little of the prescription decision can be explained by observable characteristics of individual patients, but all of the evidence indicates that physicians are indeed an important agent in determining whether patients receive either trade-name or generic drugs.

We use a unique new data set that combines individual worker data with data on workers' employers to estimate plant-level production functions and wage equations, and thus to compare relative marginal products and relative wages for various groups of workers. The data and empirical framework lead to new evidence on numerous questions regarding the determination of wages, questions that hinge on the relationship between wages and marginal products of workers in different demographic groups. These include race and sex discrimination in wages, the causes of rising wages over the life cycle, and the returns to marriage. First, workers who have ever been married are more productive than never-married workers and are paid accordingly. Second, prime-aged workers (aged 35-54) are equally as productive as younger workers, and in some specifications are estimated to receive higher wages. However, older workers (aged 55+) are less productive than younger workers but are paid more. Third, the data indicate no difference between the relative wage and relative productivity of black workers. Finally, with the exception of managerial and professional occupations, women are paid about 25-35% less than men, but estimated productivity differentials for women are generally no larger than 1570, and significantly smaller than the pay differential.