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 80.9 lists applicable boundary keys for designs that use unified family and HaybittlePeto methods, designs that use error spending methods, and designs that use the HaybittlePeto method only.
Specified Parameters 
Boundary Keys 

Method 
(Alt Ref – Max Info) 
Alpha 
Beta 
None 
Both 
Unified 
X 
X 
X 

Unified/HaybittlePeto 
X 
X 
X 

Error spending 
X 
X 
X 

HaybittlePeto 
X 
X 
X 
X 

Unified/HaybittlePeto 
X 

Error spending 
X 

HaybittlePeto 
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/HaybittlePeto" indicates that both the unified method and the HaybittlePeto 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 HaybittlePeto 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 80.10 lists applicable boundary keys for a design that uses 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.