https://doi.org/10.24928/2026/0234

Impacts of waiting-type non-physical waste on schedule deviation in lean-managed building projects in Indonesia

Abdhy Gazali¹, Anang Wirdianto², Aminullah Aminullah³, Anisah Anisah⁴, Refia Alaida⁵ & Lintang Tirta Sari⁶

Abstract

Waiting-type non-physical waste remains a common issue in construction projects, yet prior studies have mainly focused on identifying its causes rather than measuring its impact on schedule performance. Limited research has examined how waiting relates to activity-level schedule characteristics in Lean Construction practices. This study investigates how waiting-type non-physical waste contributes to schedule deviation in Indonesian building construction projects. A descriptive–quantitative approach was applied using data from four projects implementing the Last Planner System (LPS). Waiting events were identified and classified at the activity level using operational indicators derived from Lean Construction literature and LPS documentation. Schedule deviation attributable to waiting was then analyzed using a CPM-based approach incorporating activity duration and slack. The results show that labor shortages were the most frequent cause of waiting, followed by unprepared work areas and material shortages. However, waiting frequency did not directly correspond to schedule impact. Waiting affecting activities with limited slack contributed disproportionately to deviation, while shorter-duration activities showed higher proportional delays and longer-duration activities accumulated greater absolute delays. These findings highlight that waiting impacts should be assessed not only by frequency, but also by activity characteristics and schedule structure.

Keywords

Lean construction, waiting waste, non-physical waste, schedule deviation, Last Planner System, Critical Path Method.

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Reference in APA 7th edition format:

Gazali, A., Wirdianto, A., Aminullah, A., Anisah, A., Alaida, R. & Sari, L. T.. (2026). Impacts of waiting-type non-physical waste on schedule deviation in lean-managed building projects in Indonesia. In Hamzeh, F., Poshdar, M., & Garcia-Lopez,, N. P. (Eds.), Proceedings of the 34th Annual Conference of the International Group for Lean Construction (IGLC 34) (pp. 1677–1688). https://doi.org/10.24928/2026/0234

Shortened reference for use in IGLC papers:

Gazali, A., Wirdianto, A., Aminullah, A., Anisah, A., Alaida, R. & Sari, L. T.. (2026). Impacts of waiting-type non-physical waste on schedule deviation in lean-managed building projects in Indonesia. IGLC34. https://doi.org/10.24928/2026/0234