Selection, Meritocracy, and Educational Quality
| Dick Langlois |
We have all heard complaints about the decline in the quality of students over, say, the second half of the twentieth century. The usual interpretation is that this has to do with decline in the quality of schools, especially high schools, or in the curriculum delivered in those schools. I always like to point out to people (that is, to non-economists) that much of the perceived decline is likely a matter of demographic and selection effects. Access to secondary and higher education expanded tremendously after World War II, which changed the underlying distribution of abilities of students finishing high school and attending college. (This is also relevant to discussions of the quality of American college students versus Europeans or others — the fraction of students going on to college is higher in the U. S. than elsewhere, so comparing just the mean is misleading.) Education also became more meritocratic after the War, in that colleges and universities began to screen students by academic ability rather by other characteristics (like income).
I just ran across an interesting new paper by Lutz Hendricks and Todd Schoellman that analyzes these issues in a thorough and illuminating way. Here is the abstract:
Student Abilities During the Expansion of U.S. Education, 1950-2000
Since 1950, U.S. educational attainment has increased substantially. While the median student in 1950 dropped out of high school, the median student today attends some college. In an environment with ability heterogeneity and positive sorting between ability and school tenure, the expansion of education implies a decrease in the average ability of students conditional on school attainment. Using a calibrated model of school choice under ability heterogeneity, we investigate the quantitative impact of rising attainment on ability and measured wages. Our findings suggest that the decline in average ability depressed wages conditional on schooling by 31-58 percentage points. We also find that the entire rise in the college wage premium since 1950 can be attributed to the rising mean ability of college graduates relative to high school graduates.
This has a number of significant implications. As the authors point out, average ability has declined at all levels of schooling. This should color our interpretation of the much-touted fact that real wages haven’t increased much since 1960. At the same time, the wage gap between low and high levels of educational attainment has increased over time — because improved sorting has selected people of higher ability into college and selected people of lower ability out of college.