Two-level orthogonal design is called a 
fractional factorial design. These
designs require the selection of p independent generators. Although the
Plackett-Burman design is more efficient than two-level orthogonal
design, it can be inefficient for some cases such as 15-factors. It causes from
the failure of balance.
AutoDesign provides the strength-II orthogonal design
such as fractional
factorial design, which generates the table automatically. Table 1 lists the
number of trials for available factors.
Table 1 Experimental runs of two-level orthogonal design
Reference
1. Peter W.M. John, 1998, Statistical Design and Analysis of Experiments, SIAM, Philadelphia.
2. Douglas C Montgomery, 2000, Design and Analysis of Experiments, John Wiley & Sons, New York.