This paper analyzes data on 11,600 students and their teachers who were randomly assigned to different size classes from kindergarten through third grade. Statistical methods are used to adjust for nonrandom attrition and transitions between classes. The main conclusions are (1) on average, performance on standardized tests increases by four percentile points the first year students attend small classes; (2) the test score advantage of students in small classes expands by about one percentile point per year in subsequent years; (3) teacher aides and measured teacher characteristics have little effect; (4) class size has a larger effect for minority students and those on free lunch; (5) Hawthorne effects were unlikely.

This paper uses Current Population Survey data to examine whether workers who use a computer at work earn a higher wage rate than otherwise similar workers who do not use a computer at work. A variety of models are estimated to try to correct for unobserved variables that might be correlated with job-related computer use and earnings. Estimates suggest that workers who use computers on their job earn 10 to 15 percent higher wages. Additionally, the expansion in computer use in the 1980s can account for one-third to one-half of the increase in the rate of return to education.

This paper estimates the difference in compensation between company-owned and franchisee-owned fast food restaurants. The contrast is of interest because contractual arrangements give managers of company-owned outlets less of an incentive to monitor and supervise employees. Estimates based on two data sets suggest that employee compensation is slightly greater at company-owned outlets than at franchisee-owned outlets. The earnings gap is 9 percent for assistant and shift managers and 2 percent for full-time crew workers. Furthermore, the tenure-earnings profile is steeper at company-owned restaurants. These findings suggest that monitoring difficulties influence the timing and generosity of compensation.

Estimates of the effect of college selectivity on earnings may be biased because elite colleges admit students, in part, based on characteristics that are related to future earnings. We matched students who applied to, and were accepted by, similar colleges to try to eliminate this bias. Using the College and Beyond data set and National Longitudinal Survey of the High School Class of 1972, we find that students who attended more selective colleges earned about the same as students of seemingly comparable ability who attended less selective schools. Children from low-income families, however, earned more if they attended selective colleges.

We examine the reduced-form relationship between per capita income and various environmental indicators. Our study covers four types of indicators: urban air pollution, the state of the oxygen regime in river basins, fecal contamination of river basins, and contamination of river basins by heavy metals. We find no evidence that environmental quality deteriorates steadily with economic growth. Rather, for most indicators, economic growth brings an initial phase of deterioration followed by a subsequent phase of improvement. The turning points for the different pollutants vary, but in most cases they come before a country reaches a per capita income of $8000.

This paper examines the effect of skill-biased technological change as measured by computerization on the recent widening of U. S. educational wage differentials. An analysis of aggregate changes in the relative supplies and wages of workers by education from 1940 to 1996 indicates strong and persistent growth in relative demand favoring college graduates. Rapid skill upgrading within detailed industries accounts for most of the growth in the relative demand for college workers, particularly since 1970. Analyses of four data sets indicate that the rate of skill upgrading has been greater in more computer-intensive industries.

The wage differential between black and white men fell from 40 percent in 1960 to 25 percent in 1980. It has been argued that this convergence reflects improvements in the relative quality of black schools. To test this hypothesis, we assembled data on pupil-teacher ratios, annual teacher pay, and term length for black and white schools in the eighteen segregated states from 1915 to 1966. These data are linked to estimated returns to education for Southern-born men from different cohorts and states in 1960, 1970, and 1980. Improvements in the relative quality of black schools explain 20 percent of the narrowing of the black-white earnings gap between 1960 and 1980.

This paper uses job applications data to investigate the relationship between job queues and wage differentials. The main finding is that openings for jobs that pay the minimum wage attract more job applicants than jobs that pay either slightly more or slightly less than the minimum wage. This spike in the job application rate distribution suggests that ex ante rents generated for employees by an above market-level minimum wage are not completely dissipated by reductions in nonwage benefits. In addition, we find that highly unionized firms, large firms, and firms in high-wage industries tend to receive relatively many job applicants for openings.