This research estimates models of the importance of conscientiousness for socio-economic outcomes. We use measures of conscientiousness at age 16 to explain adult wages and other outcomes, such as crime, health and savings behaviour. We use several waves from the 1970 British Cohort Study. Our estimates suggest a significant and sizeable correlation between early conscientiousness and adult outcomes. Measurement error is corrected for by applying IV-techniques, errors-in-variables estimators and structural equation modelling. Investigation of the lower-order structure of conscientiousness suggests that facets related to reliability, decisiveness and impulse control are most strongly correlated with outcomes. We also investigate changes in early conscientiousness and find that persons who experience declines in the personality distribution between the ages 10 and 16 seem to be worse off in terms of a variety of socio-economic outcomes.