Data drawn from the Arizona statewide testing program were used to relate selected factors to third-grade reading achievement in a representative sample of 50 school districts. Analyses of scores on the Metropolitan Achievement Test indicated that reading scores were positively related to the average market value of single residences within the school district and negatively related to ethnic imbalance in the largest school districts. Significant differences were also found between 1970-1971 and 1971-1972 reading scores in the largest districts, suggesting that there may have been changes in reading programs. Size of district, however, was not significantly related to third-grade reading achievement. (Author/AA)