TY - CONF TI - To improve performance in complex environments, you must first understand ambiguity C1 - Singapore, Singapore C3 - Proceedings of the 34th Annual Conference of the International Group for Lean Construction (IGLC 34) SP - 1217 EP - 1228 PY - 2026 DO - 10.24928/2026/0236 AU - Chesterman, Jared AU - Rocha, Cecilia Gravina Da AD - Director and Co-Founder, ProgressAmp, Australia, jared@progressamp.com, orcid.org/0009-0004-1461-4991 AD - Senior Lecturer, Faculty of Engineering & IT, University of Technology Sydney (UTS), Australia, cecilia.rocha@uts.edu.au, orcid.org/0000-0001-6764-1724 ED - Hamzeh, Farook ED - Poshdar, Mani ED - Garcia-Lopez,, Nelly P. AB - Construction delivery has traditionally treated ambiguity as a defect to be designed out through greater definition, risk transfer, and compliance to plan. Building on the IGLC complexity stream, this paper argues that this logic is increasingly inverted in major projects delivered through multi-organisation, multi-discipline systems. In complex work, ambiguity is not only a lack of information in documents, but a normal operating condition shaped by both indeterminacy in the work itself and divergent interpretations across dense stakeholder interfaces. Drawing on Cynefin, Lean Construction complexity literature, and cognitive science, the paper explains why ambiguity persists even when technical scope is clarified, and how fragmentation of scopes, contracts, and responsibilities can stabilise local certainty while reinforcing cross-boundary misalignment. This misalignment may remain locally coherent yet systemically incompatible, accumulating as coordination debt that later appears as rework, delay, escalation, claims, and exhaustion. The paper concludes that reducing ambiguity in complex work is not a one-time front-end task, but an ongoing need. LPS and Scrum are interpreted as recurring convergence mechanisms that use cadence, transparency, planning readiness, and learning loops to shorten the lifespan of misalignment and improve delivery reliability. KW - Last PlannerĀ® System KW - complex/complexity KW - psychological safety KW - agile/scrum KW - cognition. PB - T2 - Proceedings of the 34th Annual Conference of the International Group for Lean Construction (IGLC 34) DA - 2026/06/22 CY - Singapore, Singapore L1 - http://iglc.net/Papers/Details/2532/pdf L2 - http://iglc.net/Papers/Details/2532 N1 - Export Date: 19 June 2026 DB - IGLC.net DP - IGLC LA - English ER -