Last reviewed 16 Sept 2026 · 6 min read
Origins
Lean production originated in the Toyota Production System (TPS) developed by Taiichi Ohno and others in Japan after World War II. The term "lean" was popularised by Womack, Jones and Roos in The Machine That Changed the World (1990).
Lean construction adapts these ideas to construction. The Lean Construction Institute (LCI) was founded in 1997 by Glenn Ballard and Gregory Howell, who developed the Last Planner System. Lauri Koskela (1992) argued for viewing production as flows rather than only conversions.
Lean principles
Womack and Jones' five lean principles:
- Value — define value from the customer's point of view.
- Value stream — map all steps; eliminate those that do not add value.
- Flow — make value-adding steps flow without interruption.
- Pull — produce only what the next process (customer) needs, when needed.
- Perfection — pursue continuous improvement.
Conversion view vs flow view
- Traditional (conversion) view — production is a series of conversion activities (inputs → outputs); management focuses on activity cost and productivity.
- Lean (flow) view — production also includes non-value-adding flow activities — waiting, moving, inspecting — which must be minimised; the reliability of workflow between trades is critical.
Wastes (muda) in construction
The seven wastes of TPS plus unused talent — mnemonic TIMWOODS:
| Waste | Construction examples |
|---|---|
| Transport | Double handling of materials; long distances from stores |
| Inventory | Excess materials stocked on site, deteriorating or stolen |
| Motion | Unnecessary movement of workers searching for tools |
| Waiting | Crews waiting for drawings, materials, equipment, inspections or preceding trades |
| Overproduction | Producing work ahead of need (e.g. prefabricating elements that cannot be installed) |
| Over-processing | Work beyond requirements, redundant approvals |
| Defects | Rework due to errors and poor quality |
| Skills (unused talent) | Not using workers' knowledge and ideas |
Muri (overburden) and mura (unevenness) are the other two Toyota categories of waste alongside muda.
The Last Planner System (LPS)
A production planning and control system that increases workflow reliability by involving the "last planners" — foremen and crew leaders who directly assign work.
| Level | Description |
|---|---|
| Master schedule | Milestones and overall phases — what should be done |
| Phase (pull) planning | Collaborative planning backward from milestones by trade representatives — handoffs defined |
| Look-ahead planning (typically 3–6 weeks) | Make-ready process — identify and remove constraints (drawings, materials, permits, preceding work) so tasks can be done |
| Weekly work plan | Commitments by last planners to what will be done, from tasks that are ready (sound assignments) |
| Learning | Measure percent plan complete (PPC), analyse reasons for non-completion, act on root causes |
The core idea: should → can → will → did.
Higher PPC → more reliable workflow.