Analysing Portfolios of Lean Six Sigma Projects

The widespread acceptance of Six Sigma as a systematic program of process control, planning, and improvement has led to the creation of many databases describing the performance of individual projects, timing, and the techniques used. These databases provide resources for the analysis of quality management practices. Specifically, there are three levels at which analysis can occur in this context: Micro level – lowest level dealing with individual tools and statistical methods Meso level – mid level dealing with groups of individual tools and supervisor level decision-making about method selection and timing Macro level – highest level dealing with organization and institutions and related to overall quality programs and stock performance Reviewing the literature reveals a large portion concerning macro-level decision-making, particularly the decision whether to implement a Six Sigma program at a company, e.g., Yu and Popplewell (1994), Yacout and Hall (1997), Bisgaard and Freiesleben (2000), Yacout and Gautreau (2000), and Chan and Spedding (2001). Most of this research is based on individual case studies and anecdotal evidence. A second large grouping of studies deals with the micro-level, investigating component tools and techniques for green and black belts (Hoerl 2001a). Little work is published that relates to the meso-level of mid-level managing and operational decision-making (Linderman, Schroeder, Zaheer, and Choo 2003). The uses of these databases for these types of investigation are likely being ignored at most companies for at least two reasons. First, there has traditionally been little assistance from academics in how to make sense of them. Second, the people with the most statistical expertise are involved in the individual projects and not in cross project evaluation. Most managers are not statisticians and need help in making sense of the data now available to them. The growing database of project related quality improvement activities could be useful in the empirical study of some important meso-level research and real-world questions, including determining the health of a given company’s quality system, modeling Six Sigma, optimizing the selection and ordering of component methods. According to Juran and Gryna (1980) the activities that assure quality in companies can be grouped into three processes: quality planning, quality control and quality improvement.