The Last Planner System Explained
The person who assigns the work on site, the 'last planner', is usually the one who knows whether it can actually be done. This system plans around them.
The five levels of the Last Planner System
| Level | Horizon | Who | Output |
|---|---|---|---|
| Master schedule | Whole project | Project leadership | Key milestones |
| Phase schedule (pull plan) | One phase, to a milestone | Trade leaders together | Handoffs between trades, planned backwards |
| Lookahead plan | Typically about six weeks | Project team and trades | Constraint log, tasks made ready |
| Weekly work plan | Next week | Trade foremen (the last planners) | Reliable commitments |
| Daily huddle | Today | Crews and foremen | Coordination and quick constraint removal |
How to run the Last Planner System
- Set milestones in the master schedule.
- Pull-plan each phase. Starting at the milestone, each trade states what it needs from the trade before it, working backwards. Agree handoffs and durations in the room.
- Run the lookahead. For each task in the window, list its constraints: design information, submittals, materials, equipment, labour, access, prerequisite work, inspections. Assign someone to clear each one by a date.
- Make ready. Only tasks with all constraints removed move into the pool of work that can be committed.
- Build the weekly work plan. Each foreman commits only to tasks that are ready and that their crew can complete that week.
- Hold daily huddles to coordinate and surface new problems.
- Measure PPC and record reasons for variance at the end of the week.
- Learn and act. Review the most frequent reasons and change the process, not just the next plan.
How to calculate PPC (percent plan complete)
PPC = tasks completed as planned ÷ total tasks planned for the week × 100
Example: the weekly work plan has 40 committed tasks. 34 are fully completed as planned. PPC = 34 ÷ 40 × 100 = 85%.
A task counts only if it's 100% complete. A task that's 90% done counts as not done, because the next trade still can't start. PPC measures how reliable the plan was, not how much work got done.
Typical reasons for variance
- Prerequisite work not complete
- Information or design not available
- Materials or equipment not on site
- Labour shortfall
- Weather
- Area not accessible or occupied by another trade
- Inspection not done
- Rework from defects
- Over-commitment: too much planned for the week
Common Last Planner mistakes
- Managers making commitments for the trades. The point is that the last planner commits.
- Committing to tasks that aren't ready, which guarantees a low PPC.
- Counting partly finished tasks as complete.
- Tracking PPC without reasons, so nothing is learned.
- Skipping the lookahead. Without make-ready work, the weekly plan becomes a wish list.
Where SpatialSense fits
SpatialSense doesn't run Last Planner; use your pull-planning wall or LPS software for that. It can help with two inputs. When reviewing the weekly plan, a timestamped 360° walk or scan shows whether an area really is complete and handed over, which settles "prerequisite work not complete" arguments with evidence. During the lookahead, constraints found on site can be pinned as issues at their exact location, with an owner and due date.
Frequently asked questions
What is the Last Planner System?
The Last Planner System is a lean construction method for collaborative production planning and control. It links milestone and phase planning to lookahead planning, weekly commitments by trade foremen, and daily huddles, and measures plan reliability with percent plan complete.
Who developed the Last Planner System?
Glenn Ballard and Greg Howell developed it in the 1990s. They went on to found the Lean Construction Institute.
Who is the 'last planner'?
The person who assigns work directly to the crew, usually the trade foreman or supervisor. They are the last person in the planning chain before the work is done.
How do you calculate PPC?
Divide the number of tasks completed as planned by the total number of tasks committed for the week, and multiply by 100. Only fully completed tasks count.
What is a lookahead plan?
A lookahead plan covers the next several weeks, often about six. The team identifies each task's constraints and works to remove them so the task is ready to be committed in a weekly work plan.
Does SpatialSense run the Last Planner System?
No. SpatialSense is a reality-capture platform. It can supply dated visual evidence of whether areas are complete, and track site constraints as pinned issues, alongside your Last Planner process.
Check handoffs with evidence. Start a free trial and capture a timestamped walk of the areas in this week's plan.
14 days free with no credit card, or 30 days free when you book a demo.