“…Since they have been discussed and compared by their authors (Hanna & Oaster, 1978-1979Pyrczak, 1975Pyrczak, -1976Tuinman, 1973Tuinman, -1974 and since this study concerns empirical rather than rational comparisons, their relative merits will not be treated. The indices themselves were recently republished and described in this journal (Hanna, 1979).…”