Projective properties of screening designs in economic construction of modelisation or optimisation designs

The projective properties of the screening designs pointed out by Hau and Box (Constrained experimental design: Part I, II, III. Center for Quality and Productivity Improvement, University Wisconsin, Madison, WI, USA, 1990) are used to define the optimal and economic transitional way between the screening phase and the modelisation or optimisation phase in experimental investigation: (a) project the screening design onto the active factors identified at this phase, (b) reuse the screening phase results to build the modelisation or optimisation design. nefits achieved, compared with the conventional methods, are substantial and depend on the number of the inert factors identified at the screening phase, and on the nature of the design used at this phase.