February, 2003
© 2000, 2001 Scott S. Emerson, M.D., Ph.D.
Use of
constrained families in flexible implementation of stopping
rules
At the
first analysis, compute stopping boundary from parametric family
At
successive analyses, use parametric family with constraints (on some
scale) for the previously conducted interim analyses
When the
error spending scale is used, this is just the error spending approach of
Lan & DeMets or Pampallona, Tsiatis, & Kim