Incorporating sustainability in inventory planning models: a systematic literature review of existing approaches

Sustainability has gained an increasing relevance in different supply chain management (SCM) processes. Companies undertake sustainability initiatives not only with the aim to cause less harm to the environment and the society, but also to build competitive advantage based on sustainability. Inventory planning and management (IP&M) is a cornerstone process for managing a supply chain, since the decisions regarding how much, where and for how long to keep inventories have important impact on the planning of production, purchasing and distribution. Therefore, this paper focuses on the decision-making process for IP&M and aims at investigating how the extant literature has explored the integration of it with economic, environmental and social sustainability. Notably, we adopt the Sustainable Development Goals (SDGs) framework to explore the how IP&M approaches support or hinder different sustainability objectives. Through a systematic literature review, we derive a list of 35 papers published in the main academic reference journals in Scopus database in the last 9 years. From a synthesis of available evidence, we develop a classification of the contributions along two dimensions. A first dimension is represented by the extent to which the decision-making process is focused on: i) strategic planning (e.g., location-inventory model) or ii) tactical planning (i.e., sustainable lot sizing decisions o inventory replenishment rules) decisions. A second dimension of classification is represented by the role assumed by sustainability. Sustainability ranges from being integrated in the strategic objective function of IP&M models (i.e., a sustainable economic order quantity is computed considering the minimization of the environmental impact), or as a constraint. This study aims to be the starting point for the development of a new generation of IP&M models that can become useful decision support systems for practitioners to include sustainability in their decision-making.