Fixing a factor in the sequential design of two-level fractional factorial experiments

Abstract

When designing two-level fractional factorial experiments sequentially, there is a wide choice of designs that could be used at each stage. Designs in which one of the factors is fixed at a particular level after the first experiment are studied in this paper. This sometimes allows all important effects to be estimated in fewer runs than would the standard sequences of designs, and effects can sometimes be estimated more efficiently. The properties of some sequences are presented, and extensions to fixing more than one factor and to factors with more than two levels are discussed.