برگشت به مدرسه: استفاده از تئوری سرمایه انسانی برای کارگران بالغ

There is a vast literature on the decision to enroll in higher education, but it focuses almost entirely on traditional students: 18 year olds graduating from high school. Yet less than half of students at degree-granting institutions are in the traditional 18–22 age range; nearly 40% are at least 25. This paper examines the enrollment behavior of persons 25 or older. We use data from a large-scale 1998 Department of Labor (DOL) policy demonstration in Greater Baltimore. By studying the behavior of older people we can examine factors such as age, earnings and marital status that vary little among the much-studied traditional students. Our results conform to the (rarely tested) predictions of human capital theory that age and opportunity costs are impediments to enrollment. We also find that where you live has a substantial impact on whether you return to school.

Volumes have been written about individual decisions whether to enroll in higher education. But the vast majority of studies consider only high school seniors. This focus offers a rather narrow view of higher education because less than half of students at degree-granting institutions are younger than 22. Nearly 40% are at least 25 years old (U.S. Department of Education, 2008). Ignoring nontraditional students is increasingly problematic given that the return to school of mature workers appears to be a growing phenomenon. Studies by Marcus (1986) and Light (1996), for example, found that from 20 to 40% of men in the NLSY who leave school return within a relatively few years. Our study attempts to help fill this substantial gap in the literature by examining the enrollment in higher education of non-traditional students, persons between the ages of 25 and 65. To examine the educational decisions of mature people, we take advantage of a unique 1998 policy experiment conducted by the U.S. Department of Labor in the Greater Baltimore area. It was called the Lifelong Learning Demonstration. The idea was to determine how mature (over 25) workers (there was an earnings criterion) would respond to an information campaign extolling the learning opportunities in the area's higher education community. The results were disappointing – the information campaign was insufficient to stimulate enrollment (Buron, Orr, & Patrabansh, 1999). But the project collected, from various sources, demographic information on more than 450,000 mature potential students. Administrative records of the Maryland Higher Education Commission revealed which of Maryland's 2-year or 4-year colleges, if any, these people attended between 1990 and 1998. A relatively small fraction, about 5%, did. Still, we have data on several tens of thousands of students and hundreds of thousands of non-students. Because data from administrative sources are limited, Lifelong Learning also conducted a detailed telephone survey of 3600 of the sample members. The survey sample was weighted to heavily oversample enrollees. Our study employs both the administrative data and the survey. We know of no other data set that provides nearly such a comprehensive picture of the education behavior of mature individuals. We model both the probability of enrolling in higher education and the number of credits taken once enrolled. Our results are consistent with the main hypotheses of human capital theory. Because older people have less time to recoup an educational investment, enrollment drops rapidly with age. Similarly, the human capital model predicts that opportunity costs of school, through lost earnings, should tend to discourage investment in schooling. We observe this effect strongly for attendance at community colleges, but less so for four-year institutions. Another discovery is that, consistent with trends observed among traditional students, mature women are about one third to one half more likely to pursue further education than their male counterparts. Finally, we find that where you live has a substantial impact on whether you enroll. Our results show that controlling for the effects of location is important in obtaining accurate measures of the effects of demographic variables.

This paper sought to bolster the thin literature on the higher-education decisions of mature individuals. Our main results reinforce some standard – but rarely tested – predictions of human capital theory. The likelihood of pursuing additional higher education falls rapidly with age. Opportunity costs, in the form of lost wages, are also an impediment to attending community college. Earnings seem less important for attending a four-year college, but this effect may be dampened by a likely correlation between earnings and unobserved academic ability. We found a significant difference between mature men and mature women in the probability of further education. A mature woman is about 35–50% more likely than her male counterpart to enroll in higher education. Thus, the relative feminization of higher education that we observe among traditional students seems also to apply to their older classmates.