A leanness measure of manufacturing systems for quantifying impacts of lean initiatives

Various lean tools and techniques have been developed for process improvement. In order to track the progress, lean metrics were developed correspondingly. However, an integrated and quantitative measure of overall leanness level has not been established. This paper proposes a unit-invariant leanness measure with a self-contained benchmark to quantify the leanness level of manufacturing systems. Evolved from the concept of data envelopment analysis (DEA), the leanness measure extracts the value-adding investments from a production process to determine the leanness frontier as a benchmark. A linear program based on slacks-based measure (SBM) derives the leanness score that indicates how lean the system is and how much waste exists. Using the score, impacts of various lean initiatives can be quantified as decision support information complementing the existing lean metrics.