Regarding relative contributions of common and criterion-specific influences to genetic and unique environ mental components of symptom variance, the following notable patterns are evident in Table 2: (1) Genetic common factors (rule breaking and overt aggression) contribute substantially more than criterion-specific genetic influences to 3 of the 4 most heritable symptoms (running away, fights, and hurting people) and to 2 other modestly heritable symptoms (telling lies and using a weapon). (2) Criterion-specific genetic influences contribute prominently to 2 symptoms (hooky and stealing) that evidence subsidiary contributions from one or the other genetic common factor. (3) Criterion-specific genetic influences account for most or all of the modest heritable variance in 3 of the 5 symptoms (setting fires, destroying property, and hurting animals) that define the shared environmental (ie, covert delinquency) common factor. (4) The nonshared environmental factor ac counts for more than 50% of the nonshared environmental influence in 3 of the CD criteria (destroying property, using a weapon, and hurting people), whereas criterion-specific nonshared environmental effects (which include measurement error) contribute more substantially to the other 7 criteria.
