Probit regression of general cognitive ability on violent offending (1973–2009) in Swedish men born 1961–1975, ordinary unpaired analysis and within sibling-pair, stratified by sibling type.

Notes: Numbers are probit regression coefficients with 95% confidence interval within brackets.A)Adjusted for birth year.B)Adjusted for birth year and childhood socioeconomic variables: growing up with single mother, family income, and urbanicity.C)Within-pair adjustments also included brother’s corresponding covariates.