February, 2003
© 2000, 2001  Scott S. Emerson, M.D., Ph.D.
Session 2: 94
Unified Design Family
Choice of R parameter
R > 0:
·Larger positive values of R make early stopping easier
·When R>0 and P=0, typically need A>0
·Reasonable range of values: 0.1 < R < 20
·R < 1 is convex outward
·R > 1 is convex inward
·When R>0 and P>0, can get change in convexity of boundaries