Compound Orthogonal Arrays and Dispersion Effects

After a description of the salient features of Taguchi’s methods for off-line quality improvement and a brief discussion of more recent alternatives, we focus on the use of compound orthogonal arrays for studying dispersion effects. For a dispersion analysis commonly used with these arrays, we derive properties that the arrays must possess in order for this analysis to be valid. For ease of presentation, we restrict considerations to 2-level factors. The main result is slightly more general than a result due to Rosenbaum (1994, 1996)