The contributions of school classification--regular or educable mentally retarded (EMR)--sex, and ethnic status to domain scores from the Public School Version of the Adaptive Behavior Scale were investigated. Part One measures the development of personal independence in daily living, while Part Two measures maladaptive behavior related to personality and behavior disorders. Data were collected from over 1,600 regular and EMR subjects approximately equally distributed between the sexes among white, black and Spanish-speaking subjects aged 7 to 13. Domain scores were valid for differentiating among children of different adaptive behavior levels as inferred from class placement. Ethnic status was not a unique contributor to Part One domain scores when the effects of classification were accounted for. On the Part Two domains, ethnic status was a significant contributor to some domain scores, but not at all age levels. Sex made few unique contributions to domain scores on Part One of the scale, but was a significant factor on some domains of Part Two at some age levels. It was concluded that the scale was valid for differentiating among pupils assigned to regular and EMR classes from ages 7 to 12, and that there are common expectancies for personal independence and responsibility among boys and girls from different ethnic groups. (Author/BW)