SES, as indicated by family income and parental education level, is also associated with increased likelihood of attending college. Studies have consistently shown that SES increases likelihood of attending college. Haveman and Wolfe (1995) found that the family income/poverty ratio is predictive of increased likelihood of attending college, after controlling for background factors. McNeal (1995) found that high SES students are less likely to drop out of high school. Zaff, et al. (2001) found that SES, a composite variable, comprised of parental education, parental occupation, parental employment status, and family income was predictive of college attendance. Further, Hauser and Sweeney found poverty was a stronger predictor than family structure of graduating from college. In a model including only pre-college and family background variables, SES was found to be associated with the likelihood of completing college (Adelman, 1999). When college performance, and attendance pattern controls were added, SES was moderately associated with higher levels of college completion (Adelman, 1999).