Randomization tests for systematic single-case designs are not always appropriate

The authors used a Monte Carlo simulation to examine how the violation of the exchangeability assumption affects empirical Type I error rates of the LMH randomization test (J. R. Levin, L. A. Marascuilo, T L. J. Hubert, 1978). Simulation results showed that the LMH test is not always an appropriate technique for analyzing systematic designs when data are autocorrelated. The use of both conditional and unconditional randomization distributions is proposed as a way of synthesizing the literature.