Two-level screening designs are appropriate for situations where a large number of factors (q) is examined but relatively few (k) of these are expected to be important. It is now known which of the q factors will be the important ones, that is, it is not known which k dimensions of the experimental space will be of further interest. After the results of the design have received a first analysis, the design will be projected into the k dimensions of interest. These projections are investigated for Plackett and Burman type-screening designs with q•23 factors, and k=3,4 and 5.
