Managing commitments for reliable planning: evidence from action research

Purpose Low planning reliability in construction projects has been linked to weaknesses in commitment management within the Last Planner System (LPS). While the Linguistic Action Perspective (LAP) provides a strong theoretical explanation of commitments as conversations for action, empirical evidence of operational systems that translate these principles into practice remains limited. This paper evaluates a Commitment Management System (CMS) designed to improve commitment reliability and planning performance in construction projects. Design/methodology/approach An action research approach was adopted through a longitudinal, multi-project intervention in four construction projects, two in Chile and two in Colombia, with different levels of LPS maturity. The CMS was implemented through structured interventions embedded in weekly planning meetings. Quantitative and qualitative data were collected to assess commitment-related indicators, LPS maturity, Percent Plan Complete (PPC), PPC variability, engagement behaviours, and schedule deviation. Findings The results indicate that CMS implementation increased LPS maturity levels across all projects and improved commitment performance. Projects exhibiting higher CMS assimilation and engagement showed lower PPC variability and more stable planning outcomes. Schedule deviation was reduced in all cases, with an average improvement of 5.39%, demonstrating the positive impact of structured commitment management on planning reliability. Originality/value This study provides empirical validation of an operational CMS grounded in the LAP and tested through Action Research in real construction projects, strengthening the connection between communication theory and lean construction practice.