Table 1.

Statistical power (at the two-sided 5% significance level) of the simplified design forms shown in Fig. 3, under different models for the time effect (polynomials of degree 2, 4, 6 or 8), to detect effect size δ/σ = 0.3, with K = 30, M = 100, ρ = 0.05, τ = 0.2

	Polynomial degree
Simplified form	2	4	6	8
2-phase	89%	37%	35%	22%
3-phase	90%	90%	37%	33%
4-phase	89%	89%	89%	43%
Staircase	89%	89%	89%	89%