Mosaic Plots are Useful for Visualizing Low-Order Projections of Factorial Designs

Factorial experiments are widely used in industrial experimentation and other fields. Whenever a factorial experiment is not designed as a full factorial, but as a regular or nonregular fraction thereof, choice between competing designs and interpretation of experimental results should take into consideration how the experimental plan will confound experimental effects. This article proposes mosaic plots of low-order projections of factorial designs for visualizing confounding of low-order effects. Mosaic plots are particularly useful for design and analysis of orthogonal main effect plans. The R code for the creation of the plots in this article is available online in the supplementary material.