College enrollment is defined on a monthly basis using questions that ask about each
respondent's enrollment in "regular school" in the previous year. Individuals are coded as being
enrolled in college if they are enrolled in regular school in a particular month and: (1) are enrolled in
college at the time of the interview, or (2) if they are not enrolled at the time of the interview,
completed a high school diploma or GED prior to their current enrollment. College spells are
smoothed for up to four-month gaps in enrollment to account for institutional lapses that occur over
the summer and between semesters or quarters. The NLSY questions that allow me to determine
monthly enrollment do not allow me to differentiate between enrollment in two-year or four-year
colleges. Only at graduation are respondents asked the type of degree pursued. I therefore combine
two- year and four-year college enrollment throughout the paper.