Systematic sequencing of factorial experiments as an alternative to the random order

The current study aims to discuss the use of systematic methods to generate experimental designs with good statistical properties and low costs. The research focuses on the sequence of experiments and on analysis the results of three different approaches used to build (orthogonal and non-orthogonal) two-level factorial designs, wherein sequencing is randomly or systematically performed. The study simulated the design generated by each approach in the context of an actual glass container manufacturing process, with and without the presence of linear trend effects. The results indicate that, in comparison to the random order, systematic sequences may lead to fewer factor level changes and to increased robustness to linear trend effects. Therefore, they may attach design cost and quality.