Box-Behnken designs are used to generate higher order response surfaces using fewer required runs than a normal factorial.  Box-Behnken designs place points on the midpoints of the edges of the cubical design region, as well as points at the center.

Box-Behnken designs and CCF central composite designs can be visualized as near compliments of each other. They both essentially suppress selected runs from a full factorial matrix in an attempt to maintain the higher order surface definition. For example, for three three-level variables, the full factorial run size is 27. The central composite design drops all of the middle edge nodes, resulting in only 15 runs. The Box-Behnken design is nearly the opposite in that it uses the twelve middle edge nodes and the center node to fit a 2nd order equation. A central composite design plus a Box-Behnken design becomes a full factorial with extra samples taken at the center.

 

Usability Characteristics

 

Settings

In the Specifications step, you can change the following settings of Box-Behnken from the Settings tab.