The harmonic mean and Kramer (1956) unequal n forms of the Tukey multiple comparison statistic were investigated for Monte Carlo Type I and Type II errors under conditions of assumption violations. The two major questions concerning the sensitivity of multiple comparison statistics for different types of pairwise contrasts and the affect of increasing the number of treatment levels are discussed. Neither procedure consistently out-performs the other; the choice of test depends upon the population condition(s) and the pattern of unequal cell frequencies. (Author)