Correction for “Optimal unidirectional switch designs” by Zhuozhao Zhan, Geertruida H. de Bock, and Edwin R. van den Heuvel

The authors have spotted a typographical error contained in our paper titled “Optimal unidirectional switch designs.”1 The asymptotic variance for the optimal augmented steppedwedge design provided in the bottomof page 3578 is incorrect. It should read: (Formula presented.) The relative efficiency of the optimal augmented stepped wedge design with respect to the optimal unidirectional switch design shown in Figure 6 was produced using this correct expression and no changes are further needed. No other results in the article were affected by this error.