The SEQDESIGN Procedure
Applicable Boundary Keys
In the SEQDESIGN procedure, the BOUNDARYKEY= option in the DESIGN statement specifies the types of errors to be maintained for the design. Table 9 lists applicable boundary keys for designs that use unified family and Haybittle-Peto methods, designs that use error spending methods, and designs that use the Haybittle-Peto method only.
Table 9: Applicable Boundary Keys for Designs without Whitehead Methods
| Specified Parameters | Boundary Keys | ||||||
|---|---|---|---|---|---|---|---|
| Method | (Alt Ref – Max Info) | Alpha | Beta | None | Both | ||
| Unified | X | X | X | ||||
| Unified/Haybittle-Peto | X | X | X | ||||
| Error spending | X | X | X | ||||
| Haybittle-Peto | X | X | X | X | |||
| Unified/Haybittle-Peto | X | ||||||
| Error spending | X | ||||||
| Haybittle-Peto | X | ||||||
Note that the symbol "X" under "(Alt Ref – Max Info)" indicates that both the alternative reference and maximum information are specified, and the method "Unified/Haybittle-Peto" indicates that both the unified method and the Haybittle-Peto method are used in the same design.
If the ALTREF= and MAXINFO= options are both specified, then Type I and Type II error probability levels cannot be met simultaneously if both error probabilities are specified. The BOUNDARYKEY=ALPHA option maintains the Type I error probability level 
and derives Type II error probability 
. The BOUNDARYKEY=BETA option maintains the Type II error probability level and derives Type I error probability .
If the Haybittle-Peto method is used for all boundaries, the BOUNDARYKEY=NONE option uses the specified boundary value (STOP=REJECT or STOP=BOTH) and the specified boundary value (STOP=ACCEPT) at the final stage for the design.
If the ALTREF= and MAXINFO= options are not both specified, the BOUNDARYKEY=BOTH option derives boundary values that maintain both Type I and Type II error probability levels.
Table 10 lists applicable boundary keys for a design that uses Whitehead methods.
Table 10: Applicable Boundary Keys for Whitehead Methods
| Specified Parameters | Boundary Keys | |||||||
|---|---|---|---|---|---|---|---|---|
| Early Stopping | (Alt Ref – Max Info) | Tau | Alpha | Beta | None | Both | ||
Reject  |
X | X | X | X | ||||
| Accept |
X | X | X | X | ||||
| Reject/Accept |
X | 0.25 | X | X | ||||
| Reject |
X | X | ||||||
| Accept |
X | X | ||||||
| Reject/Accept |
0.25 | X | X | X | ||||
Note that the symbol "X" under "(Alt Ref – Max Info)" indicates that both alternative reference and maximum information are specified.
If the ALTREF= and MAXINFO= options are both specified, then Type I and Type II error probability levels cannot be achieved simultaneously if both are specified. the BOUNDARYKEY=ALPHA option maintains the Type I error probability level and derives Type II error probability . The BOUNDARYKEY=BETA option maintains the Type II error probability level and derives the Type I error probability .
If the ALTREF= and MAXINFO= options are not both specified, then for a design with the STOP=REJECT or STOP=ACCEPT option, the BOUNDARYKEY=BOTH option derives boundary values that maintain both Type I and Type II error probability levels. If the STOP=BOTH option is specified, Whitehead’s triangular method produces boundaries with approximate Type I and Type II error probabilities. The BOUNDARYKEY=NONE option specifies no adjustment to these boundaries. The BOUNDARYKEY=ALPHA and BOUNDARYKEY=BETA options maintain the Type I error probability level and Type II error probability level , respectively, by adjusting boundary values at the final stage.