There are 6 materials used to create a liquid solution that is the subject of experimentation. The amounts of each material are fixed; however, we know that the order in which each is introduced can have an effect on the responses. Is there a way to design a set of experiments that can test the order of addition without having to run a full factorial?
Joe Voelkel spoke on this topic at the 2016 QPRC. He used Proc Optex to select a D-efficient subset of sequences, based on a specified (e.g., first-order) model. Contact me (email@example.com) for more ideas.