February, 2003
© 2000, 2001 Scott S. Emerson, M.D., Ph.D.
Example:
Superposed stopping rules from first and second interim analyses using
error spending
When
plotted on the sample mean scale, the monitoring bounds from the first
and second analyses will not agree if the boundary at the
first analysis is constrained on the error spending scale
This is due
to the need to estimate the statistical information