Numerous studies have found that work intensity, or weekly hours of work, is associated with decreased levels of high school completion. The National Research Council (1998), in their review of research on employment and educational outcomes, found a consistent negative association between working over 20 hours during high school and high school completion. Steinberg and Cauffman (1995), in their review of studies looking at developmental outcomes of adolescent employment, found a negative relationship between working 20 or more hours per week and years of schooling completed. Marsh (1991), in an analysis of High School and Beyond data on a sample of 10,613, found hours of employment during 10th grade to be predictive of dropping out by the 12th grade. D'Amico (1984) found that students who worked over 20 hours per week were more likely to drop out of high school than students who worked fewer than 20 hours per week. McNeal (1997), using High School and Beyond data, also found that higher levels of employment were positively, linearly related to dropping out of high school. These studies controlled for background factors. Chaplin and Hannaway (1996) use High School and Beyond data to examine the relationship between high school employment and educational attainment. Among students who were not considered to be at-risk, there was a decreased likelihood that they attained a high school diploma. They found that working over 15 hours per week during sophomore year is associated with decreased levels of school enrollment in senior year for both Blacks and Non-Blacks. They also report that students who worked low or high hours were more likely to attain a GED than students who worked a moderate number of hours. These findings remained after accounting for background factors, including prior achievement track status, history of grade retention, race, SES, and family structure, and percent of students in school who are disadvantaged.