Last Planner System (LPS) in Lean Construction
The Last Planner® System is a production-control method developed by Glenn Ballard and Greg Howell in the early 1990s and now the operational spine of most serious lean construction programmes worldwide. It does not replace CPM — it sits on top of it, closing the gap between a master schedule that says when and a site that needs to know whether it actually can. Five conversations, one metric, weeks of on-time delivery.
The Last Planner® System is a registered trademark of the Lean Construction Institute. References here are to the methodology.
What is the Last Planner System?
LPS is a pull-based production-control system that turns master-schedule should-do dates into reliable will-do commitments through weekly team dialogue, make-ready screening and continuous learning driven by a single metric — Percent Plan Complete.
Also known as: collaborative planning, pull planning, make-ready planning, reliable promising. LPS as an acronym is used interchangeably with the full name.
The five conversations of LPS
LPS is often called a five-conversation model. Each conversation operates at a different time horizon and asks a different question. The learning loop at the end feeds back into the lookahead, which is what makes the system actually improve over time rather than just record weekly numbers.
- 1
Should — the master schedule
The CPM plan sets the should-do dates. LPS respects the master; it does not throw it away. In a healthy LPS programme the CPM is baselined once, then updated with the field truth flowing back through the lookahead.
- 2
Can — the six-week lookahead
Every activity in the master is screened for constraints six weeks out: drawings, submittals, permits, materials, prerequisites, crews, equipment, safety. Anything not constraint-free by two weeks out is either resolved or pulled out of the plan.
- 3
Will — the weekly work plan
Only constraint-free activities enter the weekly commitment set. Last planners — the foremen and subcontractor leads actually doing the work — commit to what they will complete, not what the master says they should.
- 4
Did — the daily and weekly check-in
Short standing meetings track completion against commitment. This is where LPS lives or dies: the conversation is about promises kept, not tasks pending.
- 5
Learn — root-cause and PPC
Every missed commitment is coded with a reason (design, materials, prerequisite, weather, crew, other). PPC (Percent Plan Complete) is computed weekly. The reason trend drives the next lookahead.
Worked example: calculating PPC on a real week
Take a mid-project week on a mixed-use building. The team commits to eight activities on Monday. On Friday five are done, three are not. The single number that captures the reliability of that week is Percent Plan Complete.
| Commitment | Trade | Done? | Reason (if not) |
|---|---|---|---|
| Slab pour, zone A | Concreter | Yes | — |
| Rebar fix, zone B | Rebar | Yes | — |
| Formwork strip, zone A | Concreter | No | Cure time under-estimated |
| MEP first-fix, zone C | MEP | Yes | — |
| Snag list, zone D | Fit-out | Yes | — |
| Curtain wall delivery | Logistics | No | Supplier missed slot |
| Inspection sign-off, zone A | Inspector | No | Missing paperwork |
| Steel frame, level 4 | Steel | Yes | — |
PPC this week = 5 completed ÷ 8 committed = 62.5%
62.5% is not a good week — but it is a truthful one. The value is not in the number itself, it is in the reason codes. Two of the three misses were make-ready failures the lookahead should have caught (curtain wall delivery slot and inspection paperwork). One was a duration estimate error (cure time). Feed those three reasons into next week's lookahead and the following week's PPC moves — not because the team tried harder, but because the plan itself became more honest.
Industry benchmarks: mature LPS teams sustain PPC in the 75–85% range week over week. Sustained under 60% means make-ready is broken. Above 90% typically means the team is under-committing to flatter the metric.
Where LPS breaks — it is almost never the tool
LPS is a cultural change first and a scheduling change second. Every failure mode below is a version of the same root cause: the organisation adopted the artefacts (the board, the meetings, the PPC number) without the underlying commitment to reliable promising.
Sold to leadership, not the last planners
The people who actually make the commitments — the foremen and subcontractor leads — are not trained, not consulted, and often not even present at the weekly meeting. The tool becomes management theatre.
Weekly meetings become status reports
"What did you finish? What are you starting?" is a status report, not a commitment conversation. The LPS version is "What can you not commit to yet, and what would need to change so you can?" The distinction is the whole point.
No teeth on missed commitments
If missed commitments carry no cost, PPC drifts toward zero. Not punishment — but visible consequences (rescheduling downstream work, escalating the specific reason code, renegotiating scope) that make the commitment feel real.
Master and lookahead drift apart
The lookahead is maintained in a whiteboard photo. The master lives in P6. Neither reflects the other after week three. This is the failure VisiLean was built to solve — same underlying schedule seen at different resolutions, updated once.
How VisiLean digitises the LPS loop
VisiLean's Planner treats LPS as a view of the same schedule the master runs on, not a separate tool. The lookahead is pulled from the CPM; the weekly commitments write back to the CPM; PPC and reason codes accumulate in one place.
- 6-week lookahead auto-generated from the CPM master — no side spreadsheet, no whiteboard photo, no drift.
- Constraint tracking attaches to real activity IDs, so the master schedule immediately reflects what is and is not ready.
- Last planners commit and update from the LiveSite mobile app; the office sees it live, not on Friday.
- PPC and reason codes computed automatically per week, per team, per phase — trend visible to everyone.
- Reason-code trends feed back into the next lookahead so the same failure mode does not recur three weeks in a row.
Related methods
Critical Path Method (CPM)
The master schedule LPS sits on top of. Definition, worked example and how the two methods work together.
Read moreTakt planning
Rhythm-based flow for repetitive work. Complements LPS on high-repetition zones like hotel floors or infrastructure spans.
Read more4D BIM
Play the LPS-updated schedule against the 3D model so planned-vs-actual is visible as geometry, not only as a PPC number.
Read moreVisiLean Planner
The product that runs the CPM master and the LPS lookahead as two views of the same schedule.
Read moreFrequently asked questions
Who created the Last Planner System?
The Last Planner® System was developed by Glenn Ballard and Greg Howell in the early 1990s and is now maintained by the Lean Construction Institute (LCI), which holds the trademark. Any reference to LPS on this page is to the methodology, not the LCI training programme.
How do you calculate PPC (Percent Plan Complete)?
PPC = (number of weekly commitments completed as promised ÷ number of weekly commitments made) × 100. Partial completions do not count — a commitment is either done or not done. Mature LPS teams sustain PPC in the 75–85% range week over week; below 60% usually indicates broken make-ready (commitments made on work that was not actually ready), and above 90% typically means the team is under-committing to make the metric look good.
How is the Last Planner System different from CPM?
CPM produces a master schedule of what should happen and when. LPS produces reliable weekly commitments about what will happen. CPM works forward from logic; LPS works backward from what the crews doing the work say they can actually deliver. In modern lean construction, they are complementary — CPM as the master, LPS as the operational control layer that keeps CPM honest.
Can you use LPS without formal lean training on the team?
Technically yes, and many teams start that way. In practice the pattern is that LPS returns thin PPC gains on the first attempt because the weekly meetings drift into status reporting rather than commitment. A short LCI-aligned introduction for the last planners (foremen, superintendents, subcontractor leads) and one dedicated facilitator per project accelerates the shift from status to commitment considerably.
What software supports the Last Planner System?
Dedicated LPS tools include VisiLean, Touchplan and vPlanner. Sablono runs a related lean production-control model, and iPlan/BIM 360 have partial LPS features. VisiLean is unusual in that the 6-week LPS lookahead is pulled directly from the CPM master schedule in Planner, so the master and the lookahead can never drift out of sync — the two views are the same underlying schedule seen at different resolutions.
See LPS run on top of a live CPM master
VisiLean's Planner runs the CPM master and the LPS lookahead as two views of the same schedule — commitments and PPC update in real time, from the field.