Researchers use data from a longitudinal child health survey in Rochester (New York) to investigate the relationship between chronic poor health and school outcomes among children. A model is presented that relates educational outcomes--academic achievement, intelligence test results, and attendance--to children's health and other personal characteristics, family socioeconomic background, and a number of school characteristics. Statistical analysis using simultaneous linear equations confirms that health factors do affect school outcomes, but that the effect varies with the type of health problem. Attendance is reduced by those illnesses that restrict strenuous activity or that interfere with peer or school interaction. In turn, decreased attendance tends to lower achievement. Chronic psychological problems, however, reduce achievement but do not lower attendance; and chronic physical problems tend to increase achievement. Special classes or tutoring for chronically ill children seem to raise academic achievement only for those younger than around eight years old. (Author/RW)