Towards a theory of multi-tier sustainable supply chains: A systematic literature review.

Purpose - The purpose of this paper is to develop a comprehensive framework that synthesizes approaches and contingency variables to manage the sustainability of multi-tier supply chains and sub-suppliers. Design/methodology/approach - Using a systematic literature review, the authors analyse 39 studies and relevant theories to develop a comprehensive framework that integrates research efforts so far. Findings - The authors build a conceptual framework that incorporates four approaches to manage the sustainability of multi-tier supply chains. They also identify several contingency variables (e.g. power, dependency, distance, industry, knowledge resources) and their effect on the proposed approaches. Research limitations/implications - Based on the framework, six research propositions that advance the theories on multi-tier supply chain management, allow lead firms to develop comprehensive sustainable supply chain strategies and set the ground for future research in the area were developed. Originality/value - This study provides a novel framework for studying sustainability in multi-tier supply chains that goes beyond the single-tier perspective and incorporates the extended supply chain