Table 2.

Required duration of enrollment to achieve > 80% power

	Duration of enrollment (years)a
Trial design
Parallel	NAb
Traditional stepped-wedge
6-month transition	6
3-month transition	5.25
Hybrid stepped-wedge
6-month transition	4.75
3-month transition	4.5

^aDuration of enrollment is the approximate number of years required to achieve > 80% power to detect an increase from 40% to 51% in the rate of survival with favorable neurologic outcome

^bIn this context, a parallel design cannot achieve 80% power, regardless of the duration of enrollment