With two level factorial designs, you can consider all combinations (for a full factorial design) or a subset of combinations (for a fractional factorial design) of up to 15 factors at 2 levels each. To design an experiment that includes factors with multiple levels and tests all factor-level combinations, use a general full factorial design instead.
The available two level factorial designs are shown next. This
information is applicable to designs with standard response data,
as well as robust parameter
designs and reliability DOE.
This table provides information about the available combinations
of the number of factors and the number of runs. The two level
full factorial designs are displayed in white cells, and the information
shown in the cells is (number of levels)^(number of factors),
which yields the number of runs.
The two level fractional factorial designs are displayed in green, yellow and red cells, where:
The information shown in the cells is the design in 2k-p form. k represents the number of factors used in the design. The fractionality of the design is equal to 1/2p, or 2-p. Thus, the design is represented by 2k(2-p), or 2k-p. Note that in such designs, the number of generators (i.e., the factorial interactions whose effects will be aliased with the main effects of particular factors) is also equal to p.