Table 6.

The main differences between the AHE methods and the JT methods

	The JT methods	The AHE methods
Efficacy and futility boundary determination	Power family by Emerson and Fleming (1989)	Error-speeding method by Lan and De-Mets (1983)
Incorporation of correlation in power and futility boundary	Power assessment only	Power assessment and futility boundary calculations- allows evaluation of how adjusting the futility boundary by incorporating the correlations, may affect the decision-making for accepting the null hypothesis
Decision-making framework for rejecting the null hypothesis	Simple- conducts both of the efficacy and futility assessments at the same interim analyses	Flexible- allows for different timings for efficacy and futility assessments and provides savings for error spending (Type I and II errors), thus improving the efficiency (increasing power and reducing required sample sizes)
Calculation of power and sample sizes	Requires a simple iterative procedure	Requires a complex iterative procedure