Abstract
Since its initial developments, lean production has been recognized as a paradigm able to standardize processes, provide long-term benefits and open up new strategic opportunities. Nowadays literature acknowledges that process orientation and waste elimination promoted by lean production are among the enabling conditions towards Industry 4.0, considered the crucial paradigm for meeting current and future market requirements. Implementing tools and practices of lean production has even increased its importance. In this context, assessing the lean implementation level of a company is valuable for two reasons: first, it helps companies interested in Industry 4.0 to evaluate the existence of enabling conditions; second, it helps researchers to identify directions for an effective adoption of the paradigms. Due to these reasons, the present paper aims at providing a review and classification of leanness assessments in literature based on a categorical analysis suggested by Narayanamurthy and Gurumurthy (2016), at identifying their limitations (for instance focus on a specific industrial sector or a unique case study or lack of an empirical test) and possible strengths (such as benchmarking or use of scale) and at proposing a new leanness assessment tool able to overcome the limitations and to include the strengths.