WARNING: data are incomplete, 90 variables have been lost, 190 variables remained. Data from 4 different sources: children, their parents, schools and the Youth Health Service (Jeugdgezondheidsdienst, GGD). Medical history and result of recent (periodical) medical examination. Schools: expected level of secondary education / registration of school absenteeism. Children: eating habits, night's rest, importance of friendship, leisure activities: music lessons, hobbies, practice of sports, ideas about causes of sickness, experience of own health. Parents: cultural exposure, readership, volunteer work, holidays, watching tv, most important aims of upbringing ideas about health and causes of sickness: importance of doctors, medicine, food, stress, sports, hygiene etc. / eating habits of child, night's rest of child, behaviour, mental and physical condition of child. Background variables: basic characteristics/ place of birth/ residence/ housing situation/ household characteristics/ occupation/employment/ education/ religion/ readership, mass media, and 'cultural' exposure