Small Composite Designs

Small second-order composite designs were suggested by Hartley (1959). Westlake (1965) provided even smaller designs for k = 5, 7, and 9 factors, for which intricate construction methods were needed. Here, simple designs formed using Plackett and Burman (1946) designs are offered for k = 5,7, and 9. Designs with one run fewer than Westlake's for k = 5 and 7 and three fewer for k = 9 are feasible by deleting repeat points that occur in some of the designs.