Simultaneous Optimization of Mean and Standard Deviation

Checking whether process and product are satisfying or functioning according to the technical specification is not enough to assure competitiveness. Competition compels organizations to develop efforts to assure that product and process characteristics are on target values and the variability around those targets is minimal. This article proposes an alternative method for optimizing both the mean and standard deviation of a quality characteristic of the process or product. The objective function accommodates all the response types, allowing the practitioner to assign distinct weights to process mean and standard deviation and to find trade-off solutions between them, taking their relative magnitudes into account. Two classical examples from the literature are used to illustrate the feasibility of the proposed method and compare its results with those of other popular methods. A practical procedure for implementing the proposed method is also presented.