A statistical approach to interpret relative environmental performance within product categories

Purpose Levi Strauss & Co. (LS&Co.) has developed a statistical-based interpretation methodology, E-valuate T, with the primary objective of assessing the environmental impact of a product, a subassembly, or process across whole product lines. The nature of apparel manufacturing, with raw materials and manufacturing facilities all across the globe, makes comparisons between individual products inherently difficult. With the multitude of decisions at each manufacturing stage, and localized factors such as grid electricitymixes, a noncontextualized comparison between two products yields little actionable information. By assessing the life cycle impact of products and subassemblies within standardized groups of like products, or cohorts of interest, the E-valuate T methodology provides directional indication of whether or not the life cycle impacts for a given product demonstrate an improvement, that is, decreased environmental impact or otherwise as compared to the cohort. Methods Using descriptive statistics of a cohort of products or materials, in this case denim fabrics, performance is determined by percentile rankings. Final scores are expressed as readily understood performance measures of good, better, and best over business-as-usual practices. Thresholds to distinguish good, better, and best scores are based on percentile rankings of performance at the 70th, 80th, and 90th percentiles, respectively. Results and discussion In this paper we present the assessment of 26 fabrics from raw material production or extraction up to and including the dyeing and weaving of a fabric, demonstrating the ability of the E-valuate T method to assess life cycle environmental performance of a product or product component relative to a cohort of like products or components. Conclusions The E-valuate T method is a first major step in the development of a comprehensive science-based approach to measuring the environmental performance of fabrics and apparel products. The pilot assessment of the 26 fabrics has yielded results that can be used to engage both internal and external stakeholders. The E-valuate T method can address the needs of three primary stakeholders: (1) relative rankings to support decisions for product designers and developers, (2) substantiation of external claims of environmental performance, and (3) communication of environmental performance to suppliers and contractors.