Findings of a study that examined the relationship between Ohio school district income levels and student testing performance are presented in this paper. The first statistical analysis categorized districts by residents' average income, and the second analysis classified them according to the percentage of families receiving Aid to Dependent Children (ADC). Each group of districts was compared to the percentage of ninth-grade students who passed the state mathematics, reading, writing, and citizenship proficiency test during 1990-91. Findings indicate that the passing rates were significantly related to family wealth. Districts with higher average incomes had higher passing rates than those with lower average incomes, and districts with a lower percentage of ADC families had higher passing rates than those with a higher percentage of ADC families. Conclusions are that passing rates on proficiency tests reflect wealth, not school effectiveness or instructional quality, and that proficiency test scores are not a valid measure of educational quality. Two tables are included. (LMI)