Cohort crowding: how resources affect collegiate attainment

analysis is whether results we attribute to adjustments on the supply side of the higher market areinstead related to demand-side explanations. Two related concerns surface. First, relatively largecohorts may be distinguished by adverse demographic or economic shocks that have direct effectson collegiate attainment. For example, if big cohorts are distinguished by low parental educationor large family size, such “compositional effects” might account for reduced college completionrather than crowding out on the supply side of the market. Secondly, membership in a relativelylarge birth cohort may dilute educational resources at the elementary and secondary levels, whichwould also reduce college preparedness. Both types of effects imply that the change in collegedemand may be far less than a change in cohort size.To understand how compositional factors such as race, parental education, and familysize are tied to cohort size, we examined 16 year olds and their parental characteristics by statefor the 1970, 1980, and 1990 decennial Census enumerations. 30 Regressions of a particularparental demographic characteristic (e.g., share black or number of children) on the size of the16-year-old population in a state and Census year, with year and state fixed effects, provides anindication of how changes in cohort size are tied to observed demographic characteristics. Morechildren in a family imply fewer resources per child, and educational attainment—both formaland informal—is likely to be negatively affected by a decrease in the time and financial resourcesavailable to each child within the family (Becker, 1981; Willis, 1973). Similarly, other familycharacteristics such as maternal education, family structure, and race may affect the educationalresources available outside of schools.For the most part, we find effects that are not statistically significant and economicallysmall. This applies to measures of family size, parental education, and ethnicity. When we weightby state size, the only significant effect is on Hispanic ethnicity, with a coefficient of .27indicating that a 2.7% increase in the share of college-age students of Hispanic origin wouldfollow a 10% increase in the size of the 16-year-old population. Even with the upper endestimates of the effect of Hispanic origin on college completion, these compositional effectscould not explain a sizable share of the reduction of college completion with increases in cohortsize.Individuals in relatively large cohorts may also face diminished resources in elementaryand secondary schools, with these resource effects reducing college preparedness and completion.Examination of the link between resources per student at the primary and secondary levels andcohort size helps to place this question in perspective. First, resources per student are negatively30 We focus on 16 rather than 18 year olds to try to minimize the extent to which individuals mayhave moved out of the households in which they grew up.19