At present, 36 States have IAC's, and 14 States have transferred jurisdiction from the supreme court to IAC's and added additional judges to meet extreme caseload pressures. Data indicate that there has been a substantial shift in caseloads from supreme courts to IAC's: the average percent of cases decided in IAC's grew from 22 percent in 1968 to 34 percent in 1974 and 54 percent in 1985. Appellate judgeships increased 48 percent from 1970 to 1984, and half this increase was the result of adding judges or expanding IAC jurisdiction. For 15 of 18 States creating IAC's between 1968 and 1985, the median increase in cases decided in the year before the creation of IAC's and those decided by both courts in the year afterward was 70 percent. Further comparison for these States indicates that backlogs and court delays also decreased significantly after creation of the IAC's. The creation of IAC's also resulted in curtailment of the use of efficiency measures (e.g., curtailed oral arguments, use of panels) by supreme courts, although most did not adopt full-scale appellate procedures after the IAC was created.