Two strategies, derived from J. P. Schaffer (1986), were compared as tests of significance for a complete set of planned orthogonal contrasts. The procedures both maintain an experimentwise error rate at or below alpha, but differ in the manner in which they test the contrast with the largest observed difference. One approach proceeds directly to the test of the contrast with the largest difference at a reduced significance level. The other is a protected procedure, first evaluating the complete null hypothesis with an omnibus "F" test, and then proceeding to test the specific hypotheses at a more liberal significance level given that the complete null hypothesis has been rejected. Monte Carlo simulation results for three and four treatment groups indicate that the relative power of the two procedures depends on the configuration of the treatment effects contained in all contrasts. Specifically, the unprotected test favors configurations with relatively small amounts of variability due to treatment effects, while the protected test has more power in cases with a relatively large amount of treatment variability. Five data tables and one figure are included. (Author/SLD)