Figure 1.

A schematic of stepped wedge design for the Early Recognition and Response to Increases in Surgical Site Infection (Early 2RIS) Trial. The shaded cell indicates treatment status, and a white cell indicates control status. There are 12 randomization sequences (defined by the first time period during which each group of clusters crossover to intervention). There are in total 105 clusters and 13 time periods. In the Early 2RIS trial, the baseline period is one year, and each subsequent period is 3 months.