Best Practices in Lean Six Sigma Process Improvement: A Deeper Look

Chapter 4. Ultimate Trend: Improving the Rate of Improvement

This chapter zeroes in on eight companies whose inventory graphs seem to justify calling them "the leanest of the lean." As has been stated, though, the inventoryturnover evidence, reliable for groups, is less so for individual companies. Findings throughout the book, and this chapter as well, reinforce that caution. What can be said about single companies is limited, as follows:

• A multi-year decline in inventory turnover is strong—though imperfect—evidence of insufficient or weak commitment to and application of the full lean set.

• Impressive improvement in inventory turnover is a good preliminary indicator of a truly lean company. But further evidence is required on whether there is high commitment and application to the full lean set.

For ranking groups by leanness, Chapter 2 employed a scoring scheme. For sizing up individual companies, in this and later chapters, scores convert to A-B-C-D-F letter-grades, which are easier to comprehend. The grades (mirroring the point system) are:

• A (superior): A clearly improving trend of at least 10 years.

• B (good): The same (10 years of improvement), but followed by 5, 6, or 7 years of no improvement or decline.

• C (mediocre): No clear trend at all—just up and down, irregularly.

• D (poor): Years of improvement followed by at least 10 years of decline.

• F (failing): A many-year declining trend.

• B+, C+, D+, or F+ (clear improvement): 5 to 9 years of steady upward trend (jerky improvement does ...