Leading research shows the importance of non-cognitive skills for educational attainment, but advances in this research have been slowed by a common data limitation: most datasets do not contain explicit measures of non-cognitive skills. We examine a new proxy for non-cognitive skills, survey item response rates. Using a detailed national survey of American adolescents, we find that the percentage of questions left unanswered is a significant predictor of educational attainment. The fewer questions left unanswered, the higher the likelihood overall that respondents will enroll in college. We replicate our analysis using a more rudimentary dataset, of the kind typically used in program evaluations, and again find that item response rates are predictive of educational attainment. We posit that survey item response rates capture conscientiousness, a personality trait that is not explicitly measured in most surveys. Thus item response rates provide a convenient measure of non-cognitive skills. We also examine another proxy for non-cognitive skills, results on a coding speed test. Coding speed is also predictive of educational attainment, independent of cognitive ability. Our results suggest coding speed also captures conscientiousness, albeit different facets of conscientiousness than item response rates. We conclude that coding speed and item response rates can both be used to measure the impact of public policy on important non-cognitive skills.