Dynamics of relationships in triads: exploring the change of relationships in a buyer-supplier-supplier triad during a lean product development project

Purpose This study aims to explore the evolution of relationships within a buyer-supplier-supplier triad throughout the five life-cycle phases of a product development project. It applies the Industrial Network approach within the Industrial Marketing and Purchasing (IMP) framework, specifically the Activity-Resource-Actor (ARA) model, to understand business relationships. Furthermore, this research extends IMP studies on the dynamics of relationships in triads by investigating how the three ARA layers of a business relationship’s substance can explain the dynamics of relationships in a lean management empirical setting. The study revolves around the metatheoretical debate on the compatibility of the two paradigms, North American (Balance Theory and Structural Hole) and IMP (ARA model) to explain the dynamics of relationships in the buyer-supplier-supplier triad in a lean management context. Design/methodology/approach This is a case study that explores the triadic relationships of a Norwegian automotive supplier of crash management systems with its two local partners – a research organization and a production firm. The three firms are jointly engaged in the project to develop a new product. Findings The study proposes a theoretical framework to study relationship dynamics in triads based on the framework of Pardo and Michel (2015)). The study demonstrates the applicability of the concepts of Smith and Laage-Hellman (1992), Choi and Wu (2009a) and Harrison et al. (2012) concepts to explain the causes of change and Ritter’s (2000) concepts to explain the impacts of change. The findings also demonstrate the explanatory power and versatility of the ARA model at the micro level as a theory of triadic relationship states to explain the substance of change. Originality/value This paper addresses triad dynamics and responds to Möller and Halinen’s (2022) call for integrating IMP and North American perspectives by proposing a novel framework that combines the ARA model (Håkansson and Snehota, 1995) with Balance Theory (Heider, 1946) and Structural Hole Theory (Burt, 1992). Extending Pardo and Michel’s (2015) work, it introduces new interaction effects, such as the double-assistance and exit effects, and offers a layered view of triadic change. The study shows how actor bonds, resource ties and activity links evolve asynchronously, offering tools to interpret relationship transformations across lean project phases.