Relative difference in spot rotation rate, , as a function of ⟨ΔA(t)/A̅⟩ for the four period ranges of interest. For stars with P_rot between five and 11 days (blue), only stars with T_eff >  4200 K are shown for clarity. The inset shows the corresponding values for the Sun. Arrows denote the progression of the cycle phase, starting at activity minimum. Dotted lines indicate the position of the origin.