Identifying the Factors Affecting the Feasibility of Lean Production toward Sustainability in the Iranian Automotive Industry Using Grey Theory

Abstract

This study aimed to identify and prioritize the factors affecting the feasibility of transitioning from lean production toward sustainability in the Iranian automotive industry using qualitative thematic analysis and Grey Relational Analysis. This applied study employed an exploratory sequential mixed-methods design. In the qualitative phase, data were collected through a review of the literature and semi-structured interviews with 18 academic and professional experts selected purposively, with interviews continuing until theoretical saturation. The qualitative data were analyzed through open, axial, and selective coding to identify the principal dimensions and factors influencing sustainable lean production. In the quantitative phase, a researcher-developed questionnaire based on the extracted qualitative codes was administered to a population of 400 healthcare personnel in Ilam to assess the generalizability of the organizational components in a high-pressure service environment. Content and construct validity and Cronbach's alpha reliability were evaluated. Grey Relational Analysis was then used to transform uncertain judgments into grey numbers, normalize the data, calculate grey relational coefficients, and rank the identified factors. The analysis identified four overarching dimensions: technical and operational, economic and financial, environmental, and organizational and cultural. Grey Relational Analysis ranked reduction of production errors as the most influential factor (0.945), followed by process quality control (0.938), process optimization (0.931), reduction of production cycle time (0.924), and increased equipment efficiency (0.917). Waste reduction also received a high priority (0.910). Among supply-chain and technology factors, sustainable supply of raw materials ranked highest (0.840), while reduction of energy consumption was the leading environmental factor (0.735). Senior management support was the highest-ranked managerial factor (0.630). The transition toward sustainable lean production in the Iranian automotive industry should begin with operational stabilization and quality improvement, followed by supply-chain integration, digitalization, environmental efficiency, and sustained managerial and organizational support.