I would strongly consider going back to the model statement that I suggested, as it reflects the design of your study.  Eliminating terms because they aren't focal points of the study leads to mis-estimation of standard errors, and consequently faulty p-values when comparing means. So, the random statment here estimates a variance component due to group.  The statement is exactly equivalent to: random group; but the subject= syntax is more stable and faster. And it isn't surprising that adding it in affects the significance of the test.  Part of the reason is that with that in, you now have the correct error term for testing condition, where before it was being tested against the residual error.  The test against the residual is incorrect for your design. The syntax I gave you fits your design--give it a try.  I imagine that you will find significant interactions, which is where the richness of a split-plot is found.  If significant interactions are found, then simple effect (sliced) tests of condition can be set up at the various levels of role and period. Steve Denham ... View more