February, 2003
© 2000, 2001  Scott S. Emerson, M.D., Ph.D.
Session 2: 148
Evaluation of Designs
Futility measures
Consider the probability that a different decision would result if trial continued
Can be based on particular hypotheses, current best estimate, or predictive probabilities
(Perhaps best measure of futility is whether the stopping rule has changed the power curve substantially)