Last Planner System PPC Calculation

In the Last Planner System, percent plan complete (PPC) equals the number of planned activities completed 100% as promised divided by the total number of planned activities committed for the period, expressed as a percentage. At the end of the commitment period, the project team scores every promised assignment Yes or No with zero partial credit.

Under Glenn Ballard’s doctoral thesis on production control and the UC Berkeley Project Production Systems Laboratory benchmark (2020), an activity enters the weekly work plan denominator only from workable backlog after every constraint has been removed. Field teams screen upcoming work across a 3-to-12-week lookahead window (6 weeks preferred on most projects, updated weekly from the phase pull rather than dropped directly out of the master schedule), and related survey, model, and field-verification controls are on the smart jobsite technology hub.

Planning stage or metric	LPS conversation	Operating rule or formula	Primary reference basis
Phase and pull planning	Should	Establishes milestone-driven work sequence; Rule 1 retains master schedule activities unless positive knowledge shows they should not or cannot be executed when scheduled.	Lean Construction Institute LPS Topic Guide; Ballard (2000) Rule 1
Make-ready lookahead	Can	Rolling 3-to-12-week screen (6 weeks preferred, updated weekly); Rule 2 advances an activity only when the planner is confident constraints will clear on time.	Ballard (2000) Rule 2; LCI lookahead-planning standard work; City of Norman CM Clarification 004
Workable backlog release	Rule 3 gate	Rule 3 releases an activity for weekly selection only after all constraints are removed and tasks are tagged critical or non-critical in proper sequence.	Ballard (2000) Rule 3; Ballard and Tommelein (2021) Project Production Systems Laboratory Benchmark
Weekly work plan (WWP)	Will	Transfers Week 2 of the 6-week lookahead to the weekly sheet; Last Planners commit to specific completion days (or 1/2 day slots near 100% PPC).	LCI Standard Work 9; Ballard and Tommelein (2021) Project Production Systems Laboratory Benchmark
Percent plan complete (PPC)	Did	(Assignments 100% completed as planned ÷ Total assignments committed) × 100; strict Yes or No scoring with zero partial credit.	Ballard (2000); LCI percent-plan-complete standard work; Choo et al. (1998) WorkPlan
Variance root-cause review	Learn	Logs nonconformance reasons from front-line performers on every missed promise and posts the PPC bar chart where the entire team can see commitment trends.	Ballard (2000); LCI percent-plan-complete standard work; Choo et al. (1998) WorkPlan

What is the Last Planner System in construction scheduling?

The Last Planner System is a production-control framework where the person closest to the work with schedule decision-making authority commits only to assignments that have been screened and made ready for execution. In the Lean Construction Institute (LCI) topic definition, that last planner is the person closest to the work with authority to make reliable promises for the crew’s discipline. Under City of Norman Construction Manager Clarification 004, Last Planners are the subcontractor foremen and project managers overseeing the crews putting work in place, and they must have authority to make decisions and plan the work.

Steering weekly work after the master schedule is issued is a production-control problem. In a study (2012) of three military construction design-build projects managed by the United States Army Corps of Engineers at Wright-Patterson Air Force Base in Ohio, Gannon, Feng, and Sitzabee found that initial project schedules failed to forecast a reliable baseline for total cost, final duration, and activity count, with most schedule variability occurring after the 100% design benchmark. Those researchers note that the Last Planner System focuses on transformation, flow, and value in order to provide production control, and that it addresses percent planned complete of weekly work.

LCI organizes that production-control cycle around five sequential conversations: should, can, will, did, and learn. Pull planning defines what should happen to meet phase milestones. Make-ready planning removes upstream blockers ahead of time so scheduled work can happen. Weekly work planning records personal promises from specific foremen for what will happen next week. Percent plan complete measures what did finish on time, and variance analysis drives what the team learns before the next weekly cycle.

Before any task reaches a foreman’s weekly promise, Ballard (2000) requires the assignment to pass four quality tests:

1. Definition: described clearly enough that the task can be made ready and completion can be judged without ambiguity at the end of the period.
2. Sequence: ordered consistently with constructability logic and phase milestones.
3. Amount: sized to match the crew capacity available during the commitment window.
4. Soundness (practicality): backed by completed prerequisite physical work and available labor, materials, equipment, and information.

How do you run a percent plan complete calculation?

Run a percent plan complete calculation by dividing the number of committed assignments completed 100% as planned on the stated day by the total number of assignments committed on the weekly work plan, then multiplying by 100. LCI percent-plan-complete standard work uses that ratio, and Choo, Tommelein, Ballard, and Zabelle (1998) calculate weekly PPC by dividing the number of completed assignments by the total number of assignments:

PPC (%) = (Assignments Completed 100% as Planned ÷ Total Assignments Committed for the Period) × 100

In Ballard’s (2000) Pacific Contracting case study (Table 7.1), Week 1 lists 10 activities scheduled, 9 activities complete, and a reported Percent Plan Complete of 90%:

Example calculation (Ballard 2000, Pacific Contracting Week 1):
PPC = (9 completed activities ÷ 10 scheduled activities) × 100 = 90%

Watch the size of the weekly denominator when interpreting single-week swings. In that same Pacific Contracting record, weekly work plans from Week 17 through Week 23 contained no more than 4 assigned tasks. When at least one weekly assignment went unfinished in each week from Week 19 through Week 23, that small denominator capped weekly PPC at a maximum of 75%.

Binary Yes/No scoring, early finishes, and partial-credit pitfalls

Binary completion and early-finish gate: If a committed weekly task finishes 100% according to plan on or before its promised completion window, score it Yes, including early finishes completed within the committed time frame per the Project Production Systems Laboratory benchmark (2020); if any portion of the promised scope remains incomplete at review time, score the entire line No with zero fractional credit.

Ballard and Tommelein (2021) emphasize that the commitment review asks whether the crew started and finished the task as promised, accepting only Yes or No. Granting partial credit is done to improve the precision of progress measurement. In production control, Ballard and Tommelein warn that partial credit encourages doing work out of sequence, and measurements of project progress in systems that reward working out of sequence will look better than they are.

Unambiguous scope wording protects the binary count from inflation. Ballard (2000) notes that a loosely worded assignment such as “produce as many piping drawings as you can by the end of the week” allows almost any output to be marked complete, and warns that participants can mark vague tasks complete to make poor execution appear better. Pair binary scoring with LCI percent-plan-complete standard work’s visibility rule: assemble the Last Planners who made the promises in front of the Weekly Work Plan, agree together which items are complete or incomplete, and post the updated PPC bar chart where the entire jobsite team can track commitment trends.

Separating the 100% PPC goal from the 75–90% team average

Published Lean Construction references cite four distinct percentage benchmarks that serve different roles in schedule governance. Keep each figure tied to its exact source condition rather than treating 90% or 75% as the planning target:

Published PPC figure	Exact role in production control	Operational meaning for field crews	Authority source
100%	Proper system target for PPC	Represents reliable release of work; achieved by screening constraints and underloading crews with a labor-hour capacity buffer for duration variation rather than overloading resources.	Ballard and Tommelein (2021) Project Production Systems Laboratory Benchmark, Section 10 FAQ D
75–90%	Expected high-performing team average	Typical multi-week average outcome observed by LCI when Last Planners maintain accurate weekly work plans and active constraint logs.	LCI Last Planner System percent-plan-complete standard work
70–80% vs. 40%	Supervisor preparation illustration	At 40% PPC, tasks occur less than a coin flip, discouraging foremen from preparing; at 70–80% PPC, front-line preparation is far more likely to pay off.	Ballard and Tommelein (2021) Project Production Systems Laboratory Benchmark, Presupposition F
90% (9 of 10)	Reported single-week case measurement	Empirical Week 1 result from Pacific Contracting Table 7.1 illustrating the binary weekly count; never a cap on planning reliability.	Ballard (2000) PhD Thesis, Table 7.1

How does a make ready lookahead schedule screen constraints?

A make ready lookahead schedule screens upcoming phase-plan activities 3 to 12 weeks before scheduled execution (6 weeks preferred on most projects) so the team identifies and removes every blocker before a foreman promises the work. Ballard (2000) sets the lookahead horizon from project characteristics, planning-system reliability, and acquisition lead times for information, materials, labor, and equipment. Both LCI lookahead-planning standard work and City of Norman CM Clarification 004 use a rolling 6-week lookahead derived from pull planning and updated every week.

Ballard (2000) stresses that a lookahead schedule is never a simple drop-out filter of the master schedule. Across that rolling window, the lookahead performs six active engineering functions: shaping workflow sequence and rate, matching workflow against crew capacity, decomposing master schedule activities into work packages and operations, developing detailed field methods, maintaining a workable backlog of ready tasks, and revising higher-level schedules when field conditions shift.

Three explicit release rules in Ballard (2000) govern how tasks advance toward execution:

1. Rule 1 (Master Schedule): Keep scheduled activities in the master schedule unless positive knowledge exists that an activity should not or cannot be executed when scheduled.
2. Rule 2 (Lookahead Window): Admit an activity into the lookahead window, or let it advance from week to week inside that window, only if the planner is confident its constraints can be removed on schedule; otherwise retard the potential assignment to a later date.
3. Rule 3 (Weekly Release): Release an activity for selection into weekly work plans only if all constraints have in fact been removed, placing it into workable backlog in proper sequence.

Six-week make-ready clock and Constraint Log ownership

In Figure 14 of the Project Production Systems Laboratory benchmark (2020), Ballard and Tommelein map a week-by-week screening sequence across a 6-week lookahead window:

Countdown week	Make-ready screening action	Constraint and breakdown focus
6 weeks ahead	Open constraint analysis on incoming pull-plan tasks	Screen information and material constraints first because long-lead submittals, RFIs, and fabrication are hardest to clear in a short period.
End of Week4	Provisionally select operations for commitment release	Confirm remaining constraints can clear within the typical 2–3 week resolution window; break processes into operations no later than 3 weeks before scheduled start.
Week3	Design field operations	Develop detailed installation methods and surface any operation-specific skill, equipment, or access constraints revealed by that design.
Week2	Verify resource and permitting constraints	Confirm labor, equipment, tools, space, and permits; LCI Standard Work 9 transfers ready Week 2 lookahead items onto the incoming Weekly Work Plan sheet.
Week1	Commit the Weekly Work Plan	Last Planners select from constraint-free workable backlog (tagged critical or non-critical) and promise specific completion days.
Week0	Execute committed work and status PPC	Crews perform promised tasks and record binary Yes or No results plus nonconformance reasons at week's end.

LCI constraint-log standard work distinguishes a constraint from a predecessor task already drawn on the lookahead board. A constraint is an unresolved requirement standing in the way of execution, such as an unissued contract, an unapproved architectural change, or an open RFI. In Choo et al. (1998), the WorkPlan database groups recurring constraints on contract, engineering, material, labor, equipment, and prerequisite work, and states that if any listed constraint is not met, that work package should not be started or its execution will likely be slowed or interrupted. Hamzeh, Ballard, and Tommelein (2011) likewise flag tools, work space, and weather alongside prior work, information, labor, material, and equipment.

Inside that engineering checklist, Choo et al. (1998) verify whether all submittals and shop drawings have been turned in and approved and whether any requests for information remain outstanding. When open RFIs stem from unresolved overhead duct, pipe, or structural routing conflicts, resolve and close the model issue through the workflow in our BIM clash detection and MEP coordination guide before releasing the work package into workable backlog. Under LCI constraint-log standard work, every constraint discovered during the 6-week review goes into the Constraint Log with one named team member committed as its champion and an agreed resolution date.

Measuring lookahead health: Tasks Made Ready (TMR) and Tasks Anticipated (TA)

To catch broken lookahead screening before weekly PPC drops, the Project Production Systems Laboratory benchmark (2020) pairs PPC with two upstream ratios:

1. Tasks Made Ready (TMR): Measures the team’s ability to identify and remove constraints ahead of start by comparing tasks selected on the weekly work plan (Week0) against the candidate set held in an earlier lookahead week.
2. Tasks Anticipated (TA): Measures lookahead foresight by calculating the percentage of tasks on the Week0 weekly work plan that had already been anticipated in an earlier plan for that target week.

In Figure 22 of Ballard and Tommelein (2021), suppose the lookahead set at Week1 contains five tasks (ABCDE) and the committed weekly work plan at Week0 contains four tasks (ABEF). Only tasks A, B, and E appear in both sets and were made ready and selected for execution, while task F entered Week0 without having been anticipated in Week1:

Worked lookahead example (Ballard and Tommelein 2021, Figure 22):
TMR = ABE/ABDCE = 60%
TA = ABE/ABEF = 75%

What belongs on a weekly work plan in construction?

Effective weekly work plan construction restricts commitments to workable-backlog tasks that are 100% constraint-free at the start of the week, tagged as critical or non-critical, and promised by a named Last Planner to finish on a stated day or shift. LCI Standard Work 9 defines the Weekly Work Plan as the will commitment step: during the weekly subcontractor meeting, the team transfers ready Week 2 activities from the 6-week lookahead, confirms trade sequence and handoffs at the daily level, and secures each foreman’s personal promise for the day or days each task will be worked and completed.

In the Project Production Systems Laboratory benchmark (2020), Ballard and Tommelein recommend planning weekly commitments to the day or shift, tightening precision to the half day (1/2 day) only after the team consistently achieves near 100% PPC. Maintaining an accurate Weekly Work Plan sheet, whether posted with wall tags or tracked in a visible spreadsheet, has to be accurate under LCI Standard Work 9 in order to calculate a reliable PPC.

Weekly commitment and variance root-cause log structure

Whenever a promised weekly task scores No, both Ballard (2000) and Choo et al. (1998) require capturing the reason for noncompletion directly from the front-line supervisors, engineers, or craftspeople who held the assignment. Ballard emphasizes that although misses surface at the Last Planner level, root causes can sit at any organizational level, process, or function. Combining Choo et al.’s WorkPlan constraint checklist with Ballard’s nonconformance categories gives field teams a weekly commitment and variance tracking structure:

WorkPlan constraint or assignment check	Pre-week Rule 3 soundness gate	End-of-week PPC status	Documented nonconformance reason when missed (Ballard 2000 / Choo et al. 1998)
Engineering information	All submittals and shop drawings turned in and approved; zero open RFIs on the package.	No if halted; Yes only when 100% complete as planned	Faulty directives or information, for example the information system incorrectly indicated that information was available, or a design error discovered while carrying out the activity.
Materials and fabrication	All materials purchased, fabricated, delivered to site, and allocated to the crew.	No if the promised task is not completed as planned; Yes when installed on the promised day	Vendor error discovered while carrying out the activity.
Prerequisite physical work	Prior trade work complete and work area cleared before the week begins.	No if prior trade work is incomplete; early finishes inside the committed window count Yes	Faulty directives or information, for example the information system incorrectly indicated that prerequisite work was complete.
Crew sizing and assignment definition	Scope unambiguously defined; crew underloaded with capacity buffer for duration variation.	No if partially finished; a vague "as many as you can" line does not make completion unambiguous	Failure to apply quality criteria to assignments, for example too much work was planned.
Equipment, tools, and shared resources	Required equipment, tools, space, and permits reserved for the stated day.	No if the promised task is not completed as planned; Yes when met	Failure in coordination of shared resources.
Directive stability	Activity tagged critical or non-critical from the phase pull before week start.	No if the promised task is not completed as planned	Change in priority, for example workers reassigned temporarily to a hot task.

Does a high PPC mean the project is on schedule?

No. Percent plan complete measures promise reliability rather than milestone progress or labor productivity, so a jobsite can post 100% PPC and still fall behind the master schedule. In the Project Production Systems Laboratory benchmark (2020), Ballard and Tommelein note two limits: a crew can record 100% PPC and poor productivity when capacity exceeds ready work, and PPC can be 100% with excellent productivity while the project is still falling behind schedule, because progress toward scheduled completion dates rises and falls with PPC only when tasks are made ready in the right sequence and rate.

Hamzeh, Ballard, and Tommelein (2011) state Hypothesis H1 for when weekly PPC and project progress vary together. PPC will vary with project progress only when all three links hold without gaming the system:

1. Phase alignment: Lookahead tasks are drawn from a phase schedule structured to achieve the project end date and intermediate milestones.
2. Make-ready execution: Lookahead planning makes ready what should be done.
3. Criticality-ordered commitment: Weekly work plans are formed from what can be done, selected in order of criticality, without gaming the system.

When weekly PPC does not vary with project progress, Hamzeh, Ballard, and Tommelein state that a link in that chain is broken. Conversely, Ballard (2000) shows that, given quality plans, higher PPC corresponds to doing more of the right work with given resources.

Scope and workflow drivers for field teams setting up weekly PPC tracking

Before launching a rolling lookahead and binary PPC board on an active project, confirm five operational inputs across your project controls and field supervision workflow:

Setup element	Field governance requirement	Verification check
Authorized Last Planners	Designate subcontractor foremen and crew supervisors with authority to commit discipline labor.	Each foreman develops the weekly work plan and brings it to the weekly subcontractor meeting, and the Last Planner commits to the day or days each activity will be completed (City of Norman CM Clarification 004; LCI Standard Work 9).
Lookahead horizon	Select a 3-to-12-week window (6 weeks standard) matched to submittal and fabrication lead times.	Information and material constraints enter screening at Week 6; processes break into operations at least 3 weeks before start (Ballard 2000; Project Production Systems Laboratory 2020).
Constraint Log ledger	Track contract, engineering, material, labor, equipment, and prerequisite blockers separately from schedule logic.	Every open constraint lists one named champion and a committed resolution date prior to Week 1 commitment (LCI constraint-log standard work; Choo et al. 1998).
Model and survey readiness	Tie engineering constraint sign-off to verified spatial coordination and site control records.	Close MEP clearance and hard-clash RFIs via the BIM clash detection guide and align field data workflows on the smart jobsite technology hub.
Binary status and reason chart	Score weekly lines strictly Yes (100% done as planned) or No, and record missed-promise causes.	Post the weekly PPC bar chart where it is visible to the entire team, and record nonconformance reasons on missed promises (LCI percent-plan-complete standard work; Ballard 2000).

Sources

• Ballard, Herman Glenn (2000), The Last Planner System of Production Control, PhD Thesis, University of Birmingham
• Ballard, Glenn, and Iris D. Tommelein (2021), Current Process Benchmark (2020) for the Last Planner System of Project Planning and Control, Project Production Systems Laboratory, University of California, Berkeley
• Choo, Hyun Jeong, Iris D. Tommelein, Glenn Ballard, and Todd R. Zabelle (1998), WorkPlan: Constraint-Based Database for Work Package Scheduling, Proceedings, University of California, Berkeley
• City of Norman, Oklahoma (2021), Construction Manager Clarification 004: Last Planners, Rolling Six-Week Look Ahead Schedules, Weekly Work Plans, and Percent Plan Complete
• Lean Construction Institute, Last Planner System Standard Work: Lookahead Planning
• Lean Construction Institute, Last Planner System Standard Work: Constraint Log
• Lean Construction Institute, Last Planner System Standard Work 9: Weekly Work Planning
• Lean Construction Institute, Last Planner System Standard Work: Percent Plan Complete (PPC)
• Lean Construction Institute, Last Planner System Topic Reference
• Hamzeh, Farook, Glenn Ballard, and Iris D. Tommelein (2011), Rethinking Lookahead Planning to Optimize Construction Workflow
• Gannon, T. M., P. P. Feng, and W. E. Sitzabee (2012), Reliable Schedule Forecasting in Federal Design-Build Facility Procurement