In addition to evaluating the effects of literacy and numeracy on earnings, Dougherty (2003) assesses their impacts on the likelihood of college enrollment using data from the United States. Literacy and numeracy are measured by proficiency tests taken by high school students at graduation. The major results of this study suggest that numeracy affects earnings both directly and through college attendance. Literacy does not appear to have an effect on earnings, although it seems to increase the likelihood of attending college.