The index calculation uses three factors: (1) client difficulty as measured by the cumulative seriousness of all prior offenses for which the youth released from the program have been adjudicated, (2) subsequent delinquency adjudications or adult convictions for arrests within 1 year of program completion, and (3) costs. The programs are grouped into six categories, ranging from minimum risk, nonresidential, community-based programs to maximum-risk residential programs. The program accountability index uses the statistical calculation of z-scores for each of the three measures for each individual program. The average value for each measure is set at zero. Positive z-scores indicate that the program ranks above the average for the measure; a negative z-score indicates that the program ranks below the average. Figures, tables, and appended tables