A methodological comparison of three strategies for quality improvement

Quality improvement is understood by Juran to be the systematic pursuit of improvement opportunities in production processes. Several methodologies are proposed in literature for quality improvement projects. Three of these methodologies – Taguchi’s methods, the Shainin system and the Six Sigma programme – are compared. The comparison is facilitated by a methodological framework for quality improvement. The methodological weaknesses and strong points of each strategy are highlighted. The analysis shows that the Shainin system focuses mainly on the identiWcation of the root cause of problems. Both Taguchi’s methods and the Six Sigma programme exploit statistical modelling techniques. The Six Sigma programme is the most complete strategy of the three. Introduction According to Juran (1989) the activities in companies that assure quality can be grouped in three processes: (1) quality planning; (2) quality control; and (3) quality improvement. In this paper, I focus on the last process, quality improvement. It consists of the systematic and proactive pursuit of improvement opportunities in production processes to increase the quality to unprecedented levels (“breakthrough”). Typically, quality improvement activities are conducted in projects. Its proactive and project-wise nature distinguish quality improvement from quality control, which is an online process that is reactive in nature. Compare as well Ishikawa (1990, p. 201) and Taguchi’s (1986) distinction between online and ofXine quality control. The Emerald Research Register for this journal is available at The current issue and full text archive of this journal is available at www.em eraldinsight.com/res earchregister www.em eraldinsight .com/0265-671X .htm The author wishes to thank the Editor and referees for their useful comments. This paper is supported by funding under the European Commission’s Fifth Framework “Growth” Programme via the Thematic Network “Pro-ENBIS” contract reference: G6RT-CT-2001-05059. The author is solely responsible for the content and it does not represent the opinion of the community. IJQRM 21,2