Research · Forecast Integrity / 004
From Pull Plan to Promise: A Guided Walk Through the Last Planner Cycle
One workfront, followed from milestone to weekly promise to lesson learned, for readers trained in CPM and project controls
Ridvan SenturkPublished In this article
1. We already have the pieces
In the projects I have observed, upcoming work is mostly linked to constraints, with assignees, need-by dates and readiness decisions. Work with unresolved material constraints is withheld from the weekly plan. Every week we send the general contractor a full constraint report, and our foremen and superintendents take part in pull planning. The GC, in turn, publishes a lookahead and a weekly plan.
Those are substantial make-ready characteristics. From my seat, I have not established how explicit trade promises, DID, PPC and systematic learning operate, or how completely our internal process connects to the GC’s lookahead. The lookahead I receive doesn’t come with a constraint log; that tells me what I can see, not what the GC does. I therefore can’t conclude that we operate the complete Last Planner System.
The fair question is still: are we doing Last Planner? The documents alone can’t answer it. A pull-plan wall, a lookahead, a constraint log and a weekly plan are artifacts. Last Planner is the connected set of decisions, commitments and actions that should produce them. Having an artifact doesn’t show those decisions happened, and a thin-looking artifact doesn’t show they didn’t.
So this article follows one workfront on one synthetic project through the core Last Planner cycle. At each step it asks what the conversation is, what it should hand on, and what evidence would show it is really happening.
2. The cycle in one picture
The Lean Construction Institute describes the Last Planner System as five conversations: what SHOULD be done, what CAN be done, what WILL be done, what DID get done, and what we LEARN. This article uses that as a teaching model of the core cycle, not as a complete implementation specification.
The point that matters most for a CPM reader is that each conversation hands an accepted output, at an agreed time, to the next one. The phase plan hands on agreed handoffs. Make-ready hands on a stock of ready work. Weekly planning hands on promises. The week hands on a record of which promises were kept. Learning hands on changes to how the next plan is made. Behind each conversation sit decisions, physical actions and checks: removing a constraint, designing how an operation will be done, verifying a prerequisite, warning someone early when a promise is slipping.
Teaching model of the core cycle
Five conversations. Connected outputs.
- SHOULD
Agree the handoffs
Pull backward from the milestone
Hands onPhase plan - CAN
Make the work ready
Design execution; remove constraints
Hands onWorkable backlog - WILL
Make a reliable promise
Select, size and commit
Hands onWeekly promises - DID
Record the outcome
Check acceptance at the due time
Hands onKept / missed record - LEARN
Change the next plan
Find causes; assign and check action
Hands onCountermeasures
Vocabulary for the walk
| Term | Meaning in this article |
|---|---|
| Last planner | The person or group who decides what specific work will be done next, usually the foreman or crew lead |
| Lookahead | The rolling planning window, often several weeks, in which upcoming work is broken down and screened |
| Make-ready | The actions that remove constraints and design how the work will be executed |
| Constraint | An unresolved condition that prevents the defined work from being executed or completed as required. Here the term means a production constraint, not a CPM software date constraint |
| Workable backlog | Work assessed as ready and therefore eligible for commitment |
| Promise | A commitment by a last planner to complete defined work, for a named recipient, by an agreed time, to agreed acceptance criteria |
| Accepted | The recipient has confirmed the work meets the acceptance criteria |
| PPC | Percent Plan Complete: promises completed and accepted as promised, divided by promises made |
The current benchmark by Ballard and Tommelein states: “Now the functions of project controls are absorbed into the LPS” (2021, p. 4). Where the master schedule, labour forecast and weekly production planning are managed by different people or systems, though, their information routes need to be explicit. Section 11 takes that up.
The project we will follow
Riverside Station Electrical is a synthetic example: a fictional underground transit station fit-out. The GC owns the master schedule and facilitates pull planning; we are the electrical subcontractor. We follow one workfront, Zone P2 of the platform level, from a milestone in March 2027 back to the week of 18–22 January. Every number comes from one controlled dataset (DS-1 to DS-10, at the end), which also feeds the visuals. To avoid confusion, promises are written “promise P1” and areas “Zone P1”.
3. SHOULD: from milestone to handoff network
Start with what “done” means
The GC’s master schedule carries a milestone: platform Zones P1–P3 permanent power energised and ready for systems integration testing by Monday 15 March 2027. For teaching, four conditions make it checkable: distribution feeders terminated and insulation-tested, panels labelled, the authority’s electrical inspection passed, and utility energisation witnessed. This is a selection for teaching, not a commissioning checklist.
In our P6 schedule, that milestone touches several control activities, among them “P2 concourse branch rough-in”, “P2 corridor containment”, “P2 distribution (LP-P2 + F-P2)” and “Platform energisation support”. They are part of the milestone’s scope, not all of it.
Synthetic example
One workfront, four planning products
- 01
GC · milestone horizon
Master milestone
Zones P1–P3 permanent power energised and ready for systems integration testing · Mon 15 Mar
- 02
Electrical subcontractor · control schedule
Selected control activities
Concourse branch rough-in · corridor containment · distribution · platform energisation support
- 03
GC + trade performers · phase horizon
Agreed handoff network
Concourse and distribution branches. Other-zone readiness is a summarized prerequisite for common energisation.
- 04
Lee · weekly commitment
Promise P1: Hangers, Zone P2 concourse GL1-4
Recipient: A. Kowalski. Acceptance: Rev C positions; QA tag · due Wed 20 Jan, 15:30
Underlying records: DS-1 scenario · DS-2 dependencies · DS-6 promises
Plan backward, as a network
The GC calls a pull-planning session for the platform phase. Our superintendent and foremen attend, with mechanical, fire protection, ceilings, the utility coordinator and the GC superintendent. The benchmark says such sessions “should involve all who are responsible for delivering the work and with authority to make decisions” (Ballard and Tommelein 2021, p. 18).
Planning starts at the milestone and works backward, asking at each step what the next performer needs and by when. For Zone P2 the answer is two branches, set by the access arrangement. Branch conduit and sprinkler mains run above the public-concourse ceiling, so close-in will hide them and a pre-cover inspection must come first. Feeder F-P2 runs in cable tray in the back-of-house service corridor, which has no ceiling.
- Concourse branch: ceiling-space drawing rev C approved → mechanical ductwork → branch conduit, alongside sprinkler mains → pre-cover inspection (planned Tue 9 Feb) → ceiling close-in.
- Distribution branch: corridor ductwork → corridor cable tray; panel LP-P2 set on the wall; feeder cable delivered and prepared → pull and terminate F-P2 → insulation test → authority electrical inspection → energisation, which also needs the utility’s outage window on Monday 22 February.
In this example, the feeder route depends on corridor containment and distribution readiness. It does not depend on completion of every concourse branch-conduit task, and ceiling close-in controls concealment, not energisation.
Boundary note. This selected network follows the Zone P2 workfront. Energisation of Zones P1–P3 also requires the other zones’ readiness and the project’s specified inspection, testing and authorisation conditions. Those are summarised as one prerequisite, not detailed here.
Each handoff is stated as a request with a time. The feeder crew lead, J. Ortiz, asks Patel’s crew for “a continuous corridor tray from LP-P2 to the riser, bonded, by Thursday 21 January.” The feeder crew can start pulling on Monday 1 February, when it becomes available.
Durations first, then contingency where it’s needed
Ballard and Howell’s phase-scheduling steps say to “[a]pply durations to each activity, with no contingency or padding in the duration estimates” (2003, Phase Scheduling, step 4). Spare time is then allocated to the most fragile activities, with any remainder held as a general contingency for the phase (steps 7 and 11). Where to put it also depends on commercial arrangements. Under collective performance arrangements part of the buffer may sit at the end; where participants have separate commercial interests, it should go to activities that are both critical and uncertain (Ballard and Tommelein 2021, p. 20). Riverside’s fictional assumption is a conventional GC–subcontract.
On a Monday–Friday calendar, the planned feeder sequence is:
- Cable on site Mon 25 Jan; receiving inspection and preparation Mon 25 – Tue 26 Jan (2 working days).
- Delivery float: Wed 27 – Fri 29 Jan (3 working days), because the pull is fixed by crew availability on 1 February.
- Pull and terminate F-P2 Mon 1 – Thu 4 Feb (4 days); insulation test Fri 5 Feb (1 day).
- Interface protection: Mon 8 – Thu 11 Feb (4 working days) before the authority inspection, booked for Fri 12 Feb at 07:00.
- Re-inspection allowance (GC-held): Mon 15 – Fri 19 Feb (5 working days) before the fixed utility window on Mon 22 Feb.
- Residual reserve (GC-held): between energisation on 22 February and the 15 March milestone, shared across all three zones.
The utility window is a fixed event, not a buffer. The protection is the intervals in front of it. Each is counted once.
Synthetic example
Pull backward through two branches
Fictional assumption: separate commercial interests · conventional GC–subcontract
Agreed handoffs
Concourse · concealed work
- Mechanical ductwork
- Branch conduit + sprinkler mains
- Pre-cover inspection
- Ceiling close-in
Distribution · open corridor
Corridor tray
Promise P5Panel LP-P2
Promise P7Cable received
and prepared
- Pull + terminate F-P2
- Insulation test
- Authority inspection
Fri 12 Feb, 07:00 - Energisation
Also needs the utility window Mon 22 Feb and Zones P1/P3 readiness
Zones P1–P3 ready for systems integration testing
Where the time protection lives
Consumed by the delivery slip
3 of 4 working days consumed
Unchanged before the utility window
2027-02-23..2027-03-12, shared by Zones P1-P3
Dependency list & dated comparison
- Concourse ductwork → branch conduit, alongside sprinkler mains → pre-cover → ceiling close-in.
- Corridor ductwork → corridor tray; tray + LP-P2 + prepared cable → feeder pull and termination → insulation test → authority inspection.
- Authority inspection + utility window + other-zone readiness → energisation → milestone. Ceiling close-in is not a predecessor of energisation.
| Step | Original | Revised |
|---|---|---|
| Cable delivery | Mon 25 Jan | Tue 2 Feb |
| Receiving / preparation | Mon 25 Jan → Tue 26 Jan | Tue 2 Feb → Wed 3 Feb |
| Pull + terminate | Mon 1 Feb → Thu 4 Feb | Thu 4 Feb → Tue 9 Feb |
| Insulation test | Fri 5 Feb | Wed 10 Feb |
| Interface protection | Mon 8 Feb → Thu 11 Feb | Thu 11 Feb |
| Authority inspection | Fri 12 Feb, 07:00 | Unchanged |
| GC re-inspection allowance | Mon 15 Feb → Fri 19 Feb | Unchanged |
| Utility window | Mon 22 Feb | Unchanged |
| Milestone | Mon 15 Mar | Unchanged |
Selected network only. The other zones’ readiness and required testing/authorisation conditions are summarized; this is not a commissioning checklist.
DS-1 Scenario & conventions Inspect the records
| Scenario | Recorded basis |
|---|---|
| Project | Riverside Station Electrical — fictional underground station fit-out; GC owns master schedule and facilitates pull planning; electrical subcontractor perspective |
| Commercial assumption | Conventional GC–subcontract; separate commercial interests |
| Calendar | Mon-Fri; 07:00-11:00 and 11:30-15:30; no holidays modelled |
| Labour | 13 electricians in 5 crews; foremen Lee, Patel, Okafor excluded |
| Time convention | Illustrative person-hours charged to defined tasks, including preparation, movement, coordination, checks, waiting and handover. Not measured productivity. Internal-recipient acceptance included once in existing allocations; external recipients excluded. Acceptance timestamps are final acknowledgment. Equal planned and actual hours on kept promises is a simplifying assumption. |
| Internal acceptance charging | A. Kowalski: promise P1 acceptance charged within P1 Wed (LeeA); S. Ahmed: promise P4 acceptance charged within P5 Wed (PatelB) |
| Milestone | Permanent power energised and ready for systems integration testing · Mon 15 Mar |
| Teaching conditions | Feeders terminated and insulation-tested; panels labelled; authority inspection passed; utility energisation witnessed. Selected conditions, not a commissioning checklist. |
| Access | Concourse branch work is concealed at ceiling close-in; the corridor feeder route has no ceiling. Cable is available at the start of its delivery day. |
| Equipment | Lift-1: scissor lift; Lee A from Mon 18 Jan, 07:00; Lift-2: scissor lift; Lee B from Wed 20 Jan, 11:30; RS-1: rolling scaffold; Patel A from Mon 18 Jan, 07:00 to Wed 20 Jan, 15:30 → Okafor from Thu 21 Jan, 07:00; RS-2: rolling scaffold; Patel B from Mon 18 Jan, 07:00 |
| Housekeeping pad | Set LP-P3 on housekeeping pad; Anchored on accepted pad, level. Pad pour rescheduled 2027-01-27; acceptance for anchoring TBC |
| Internal recipients | A. Kowalski: Lee A lead hand; T. Nguyen: Lee B lead hand; S. Ahmed: Patel B lead hand |
| M. Clarke | GC superintendent |
| D. Moreau | QA lead |
| J. Ortiz | Feeder crew lead |
| Selected control activities | Concourse branch rough-in; corridor containment; distribution; platform energisation support |
| Feeder dates | Cable delivery: Tue 2 Feb; Receiving / preparation: Tue 2 Feb → Wed 3 Feb; Pull + terminate: Thu 4 Feb → Tue 9 Feb; Insulation test: Wed 10 Feb; Interface protection: Thu 11 Feb; Authority inspection: Unchanged; GC re-inspection allowance: Unchanged; Utility window: Unchanged; Milestone: Unchanged |
DS-2 Dependencies & feeder dates Inspect the records
| From | To | Handoff type |
|---|---|---|
| Coordinated ceiling-space drawing approved | Mechanical ductwork; branch conduit; sprinkler mains | Phase |
| Mechanical ductwork in concourse / corridor | Corridor cable tray; branch conduit | Phase |
| Corridor tray (promise P5); panel (promise P7); feeder cable received and prepared | Pull + terminate F-P2 | Phase |
| Pull + terminate F-P2 | Insulation test | Phase |
| Branch conduit; sprinkler mains | Pre-cover inspection planned Tue 9 Feb | Phase |
| Pre-cover inspection | Ceiling close-in | Phase |
| Insulation test | Authority inspection Fri 12 Feb, 07:00 | Phase |
| Authority inspection; utility window Mon 22 Feb; other-zone readiness | Energisation of all platform zones | Phase |
| Energisation | Milestone Mon 15 Mar | Phase |
| Promise P1 accepted Wed 20 Jan, 15:30 | Promise P2 | Within week |
| Promise P4 accepted Wed 20 Jan, 15:30 | Promise P6 | Within week |
| RS-1: Patel A releases Wed 20 Jan, 15:30 | Promise P9; Okafor from Thu 21 Jan, 07:00 | Equipment |
| Branch conduit completed the previous week | Promise P9; promise P10 walk scope | Prior week |
| LP-P3 set and accepted | Compare accepted-pad date with 5 Feb F-P3 release; consequence not established | Phase |
4. CAN: making Zone P2 ready
The phase plan says what should happen. The lookahead asks what can be done when it’s due, and what it will take. Ballard’s thesis is direct: the lookahead schedule is not a simple drop-out from the master schedule (Ballard 2000, p. 3-6). Filtering a schedule to the next six weeks gives a date range, not a screened window.
Break the work down, and design it
As “P2 concourse branch rough-in” enters the window, Lee, the conduit foreman, and our superintendent break it into operations a crew can do and check within a week: hangers for grid lines 1–4, conduit for 1–4, hangers for 4–8, conduit for 4–8, pull boxes, and the pre-cover walk. They also decide how: which lift serves which bays, hanger spacing against the coordinated drawing, and where material is staged. Ballard lists developing execution methods among the lookahead’s functions, alongside making work ready (p. 3-7, Table 3.1).
Screen, record, decide
Each operation is screened against information, materials, prerequisite work, equipment, access, permits and labour. Every constraint is tied to the work it blocks, with an owner and a need-by date taken from that work. Four things are recorded separately for each operation, because they can disagree:
- Assessed readiness: what the team concluded at the 15 January review.
- Evidence: what that conclusion rested on.
- Predecessor release: when the work in front is expected to hand over, and when it actually does.
- Release decision: whether the operation may enter next week’s commitments.
Synthetic example
A status needs evidence
A booking is evidence of an arrangement. It does not establish that equipment will be available for the work.
P3 · Hangers, Zone P2 GL4-8
Known at the 15 January review
Assessed: ready
Written supplier booking for Lift-2 only (C-018)
C-018 · Our superintendent · needed Mon 18 Jan, 07:00
What happened afterward
Lift-2 arrived Wed 20 Jan, 11:30.
The readiness assessment was wrong. The booking alone did not establish readiness.
Explore the full make-ready board and constraint list
Commitment review · Fri 15 Jan. Later findings are labelled separately; they were not known at the review.
Hangers, Zone P2 concourse GL1-4
- Known at the 15 January review · evidence
- C-014 closed; ductwork walked 14 Jan; Lift-1 on site
- Constraint / owner
- C-014 · GC design manager
- Need by
- Mon 11 Jan
- What happened afterward / handoff record
- No predecessor release recorded
- Decision at review
- Released into commitments
Conduit run, Zone P2 GL1-4
- Known at the 15 January review · evidence
- Material on site
- Constraint / owner
- No open constraint recorded
- Need by
- Not separately recorded
- What happened afterward / handoff record
- P1 accepted Wed 20 Jan, 15:30 → Thu 21 Jan, 07:00
- Decision at review
- Release conditional on predecessor; scheduled for planned start
Hangers, Zone P2 GL4-8
- Known at the 15 January review · evidence
- Written supplier booking for Lift-2 only (C-018)
- Constraint / owner
- C-018 · Our superintendent
- Need by
- Mon 18 Jan, 07:00
- What happened afterward / handoff record
- Lift-2: expected Mon 18 Jan, 07:00 → arrived Wed 20 Jan, 11:30
- Decision at review
- Released into commitments
▲ Later finding: assessment wrong. The evidence did not establish readiness.
Cable tray, Zone P1 remaining bays (excl. edge bays)
- Known at the 15 January review · evidence
- Area clear; material on site; RS-1
- Constraint / owner
- No open constraint recorded
- Need by
- Not separately recorded
- What happened afterward / handoff record
- No predecessor release recorded
- Decision at review
- Released into commitments
Cable tray, Zone P2 service corridor
- Known at the 15 January review · evidence
- C-017 closed; RS-2
- Constraint / owner
- C-017 · Mechanical superintendent
- Need by
- Mon 18 Jan
- What happened afterward / handoff record
- No predecessor release recorded
- Decision at review
- Released into commitments
Tray bonding, Zone P1
- Known at the 15 January review · evidence
- Test kit booked
- Constraint / owner
- No open constraint recorded
- Need by
- Not separately recorded
- What happened afterward / handoff record
- P4 accepted Wed 20 Jan, 15:30 → Thu 21 Jan, 07:00
- Decision at review
- Release conditional on predecessor; scheduled for planned start
Set + anchor LP-P2 (wall)
- Known at the 15 January review · evidence
- Panel on site; wall backing verified
- Constraint / owner
- No open constraint recorded
- Need by
- Not separately recorded
- What happened afterward / handoff record
- No predecessor release recorded
- Decision at review
- Released into commitments
Set LP-P3 on housekeeping pad
- Known at the 15 January review · evidence
- GC weekly update: poured (C-022)
- Constraint / owner
- C-022 · GC superintendent
- Need by
- Tue 19 Jan, 11:30
- What happened afterward / handoff record
- Pad acceptance not established
- Decision at review
- Released into commitments
▲ Later finding: assessment wrong. The evidence did not establish readiness.
Pull boxes, Zone P1
- Known at the 15 January review · evidence
- Zone P1 conduit complete prior week; RS-1 from Patel A Wed 15:30
- Constraint / owner
- No open constraint recorded
- Need by
- Not separately recorded
- What happened afterward / handoff record
- RS-1: Wed 20 Jan, 15:30 → Thu 21 Jan, 07:00
- Decision at review
- Release conditional on predecessor; scheduled for planned start
Joint QA walk, Zone P1 branch conduit (prior week); punch list. Not an authority inspection; not permission to close in
- Known at the 15 January review · evidence
- Walk booked Mon 11 Jan
- Constraint / owner
- No open constraint recorded
- Need by
- Not separately recorded
- What happened afterward / handoff record
- No predecessor release recorded
- Decision at review
- Released into commitments
‖ F-P2 pull · constrained
Our PM · need by Mon 25 Jan · Supplier notice: ETA 2027-02-02
Decision: not released. open; escalated 2027-01-15
‖ Zone P1 edge-bay tray · held back
Our safety lead · need by Wed 13 Jan · Method statement not approved
Decision: not released. open
Constraint list — the same records, before the work decision
C-014 · closed
GC design manager · need by Mon 11 Jan
Approved drawing issued
C-017 · closed
Mechanical superintendent · need by Mon 18 Jan
Walked 14 Jan
C-018 · marked cleared
Our superintendent · need by Mon 18 Jan, 07:00
Written supplier booking only
C-022 · marked cleared
GC superintendent · need by Tue 19 Jan, 11:30
GC weekly update: poured
C-015 · open; escalated 2027-01-15
Our PM · need by Mon 25 Jan
Supplier notice: ETA 2027-02-02
C-021 · open
Our safety lead · need by Wed 13 Jan
Method statement not approved
This view omits the work link and release decision to show what an issue list alone cannot explain.
Native records: DS-3 constraints · DS-4 operation readiness
Two assessments on the 15 January board will turn out to be wrong, and the evidence column shows why. The second scissor lift for hangers GL4–8 is assessed ready on a written supplier booking for Monday 07:00, not a lift on site. The LP-P3 housekeeping pad is assessed ready because the GC’s weekly update lists it as poured. But the panel’s acceptance condition is anchoring on a pad accepted for anchoring, and “poured” doesn’t establish that.
A third item is already known to be late. The supplier has moved the F-P2 feeder cable from 25 January to 2 February. That is escalated to the GC at the 15 January meeting (section 11), not discovered the following week.
DS-3 Constraint log Inspect the records
| Constraint | Blocks | Owner | Need by | Status / evidence |
|---|---|---|---|---|
| C-014 | Concourse operations | GC design manager | Mon 11 Jan | closed · Approved drawing issued |
| C-017 | P5 | Mechanical superintendent | Mon 18 Jan | closed · Walked 14 Jan |
| C-018 | P3 | Our superintendent | Mon 18 Jan, 07:00 | marked cleared · Written supplier booking only |
| C-022 | P8 | GC superintendent | Tue 19 Jan, 11:30 | marked cleared · GC weekly update: poured |
| C-015 | F-P2 pull | Our PM | Mon 25 Jan | open; escalated 2027-01-15 · Supplier notice: ETA 2027-02-02 |
| C-021 | Zone P1 edge-bay tray | Our safety lead | Wed 13 Jan | open · Method statement not approved |
DS-4 Readiness & release Inspect the records
| Operation | Assessment at commitment | Evidence | Predecessor release | Decision |
|---|---|---|---|---|
| Promise P1: Hangers, Zone P2 concourse GL1-4 | ready | C-014 closed; ductwork walked 14 Jan; Lift-1 on site | No predecessor release recorded | Released at commitment |
| Promise P2: Conduit run, Zone P2 GL1-4 | ready on release | Material on site | P1 accepted Wed 20 Jan, 15:30 → Thu 21 Jan, 07:00 | Conditional release for planned start |
| Promise P3: Hangers, Zone P2 GL4-8 | ready — later found wrong | Written supplier booking for Lift-2 only (C-018) | Lift-2: expected Mon 18 Jan, 07:00 → arrived Wed 20 Jan, 11:30 | Released at commitment |
| Promise P4: Cable tray, Zone P1 remaining bays (excl. edge bays) | ready | Area clear; material on site; RS-1 | No predecessor release recorded | Released at commitment |
| Promise P5: Cable tray, Zone P2 service corridor | ready | C-017 closed; RS-2 | No predecessor release recorded | Released at commitment |
| Promise P6: Tray bonding, Zone P1 | ready on release | Test kit booked | P4 accepted Wed 20 Jan, 15:30 → Thu 21 Jan, 07:00 | Conditional release for planned start |
| Promise P7: Set + anchor LP-P2 (wall) | ready | Panel on site; wall backing verified | No predecessor release recorded | Released at commitment |
| Promise P8: Set LP-P3 on housekeeping pad | ready — later found wrong | GC weekly update: poured (C-022) | Pad acceptance not established | Released at commitment |
| Promise P9: Pull boxes, Zone P1 | ready on release | Zone P1 conduit complete prior week; RS-1 from Patel A Wed 15:30 | RS-1: Wed 20 Jan, 15:30 → Thu 21 Jan, 07:00 | Conditional release for planned start |
| Promise P10: Joint QA walk, Zone P1 branch conduit (prior week); punch list. Not an authority inspection; not permission to close in | ready | Walk booked Mon 11 Jan | No predecessor release recorded | Released at commitment |
| B1: Lighting fixture pre-assembly, laydown | Ready | Frozen backlog record | — | Not promised |
| B2: Zone P3 concourse hanger floor marking (work for week of 1 Feb) | Ready | Frozen backlog record | — | Not promised |
| B3: Zone P3 corridor tray bracket pre-fabrication, laydown | Ready | Frozen backlog record | — | Not promised |
| F-P2 pull | constrained | C-015 | — | Not released |
| Zone P1 edge-bay tray | held back | C-021 | — | Not released |
Ballard’s release rule is that scheduled activities are released for selection into weekly work plans only if all their constraints have been removed (Ballard 2000, p. 3-18, Rule 3). Coordination continues after release, but release depends on readiness.
Constraint tracking or make-ready?
| Comparison | Constraint tracking | Make-ready |
|---|---|---|
| Records constraint, owner, assignee | Yes | Yes |
| Reports on a cadence | Yes | Yes |
| Ties each constraint to specific upcoming work | Optional | Required |
| Need-by date comes from that work | Optional | Required |
| Decides each operation's readiness from evidence | Not needed | Required |
| Keeps unready work out of commitments | Not governed | Required |
| Designs how the operation will be done | Not needed | Part of the lookahead |
5. The workable backlog
The output of CAN is a ready-work inventory. It is distinct from a list of activities whose scheduled dates are approaching. Ballard and Tommelein: “Commitment can be made only to workable backlog tasks” (2021, p. 13). Their principles describe the backlog as ready work held “to buffer against capacity loss and time loss” (p. 10).
At the 15 January meeting, ten scopes are assessed as ready, or as due for release by a predecessor during the week (two of those assessments will prove wrong). Three more ready scopes are deliberately left unpromised, each independent of the week’s promised areas and of the second lift:
- B1 Lighting fixture pre-assembly in the laydown area, 60 planned hours.
- B2 Floor marking for Zone P3 concourse hangers, work planned for the week of 1 February, 40 planned hours.
- B3 Zone P3 corridor tray bracket pre-fabrication in the laydown area, 48 planned hours.
They are the fallback if a promised task is blocked mid-week. Two other items aren’t eligible. Pulling feeder F-P2 is constrained by the cable delay. The Zone P1 edge-bay tray is held back because its working-at-height method statement isn’t approved. Both stay visible.
See the ready-work spread in V5.
6. WILL: the weekly promise
CAN produces work that is eligible for commitment. WILL turns selected work into promises made by the people who will perform it or direct the crew. In their discussion of commitment at different planning levels, Ballard and Howell state that weekly promises should cover constraint-free work “the promiser is convinced she can deliver”. The later benchmark likewise requires commitments to come from workable backlog (Ballard and Howell 2003, PDF p. 11; Ballard and Tommelein 2021, p. 13).
What a promise has to name
On Riverside, every promise names the promiser, an accountable recipient, scope and location, acceptance criteria, and a due day and time. Here is one, as it sits on the board:
Promise P5 · Cable tray, Zone P2 service corridor Promiser: Patel (crew B, 2 electricians) · Recipient: J. Ortiz, feeder crew lead Acceptance: continuous route from LP-P2 to the riser, bonded, walked and accepted by the recipient · Due: Thu 21 Jan, 15:30 · Planned: 48 h, Mon–Wed
Ballard and Howell suggest making “customer acceptance explicitly the measure of release; i.e., task completion” (2003). So a promise counts as kept only when the recipient has accepted the work by the due time. On Riverside, the acceptance time is recorded for every kept promise. Where the recipient is one of the 13 electricians, the acceptance is charged once inside an existing task allocation, not added as unrecorded time.
Sizing by crew and by day
The week runs Monday 18 to Friday 22 January, 07:00–15:30 with a 30-minute break: 8 working hours a day. Thirteen electricians in five crews give 520 nominal person-hours. The three foremen are additional, and their hours are excluded from every total. The ten promises carry 424 planned hours, and every one is allocated to a crew and a day. No crew-day exceeds its nominal hours. These are illustrative person-hours charged to tasks, including preparation, movement, checks and waiting; they are not measured installation output.
Two allocations deserve a closer look:
- Promise P4, Zone P1 cable tray, 48 hours for Patel’s two-person crew A. It is due Wednesday 15:30, the earliest time two people can deliver 48 hours under the eight-hour allocation model (2 × 3 days × 8 h). The crew is fully loaded for three days with no float, which the foreman accepts knowingly.
- Lee’s crew A is loaded 120 of 120 hours (promises P1 and P2). The 96 unpromised hours elsewhere on the platform don’t protect it. They sit with other crews, in other areas, on other equipment. Aggregate spare capacity isn’t a crew buffer.
Predecessor handoffs inside the week are planned explicitly. Promise P6 (Zone P1 tray bonding) starts Thursday because it needs promise P4’s tray accepted on Wednesday. Promise P2 (conduit GL1–4) starts Thursday because it needs promise P1’s hangers accepted on Wednesday. Rolling scaffold RS-1 passes from Patel’s crew A, once promise P4 is accepted at 15:30 on Wednesday, to Okafor’s crew for promise P9 at 07:00 on Thursday.
Synthetic example
Ready work becomes a promise
A feasible promise connects defined work, available crew time and a recipient’s acceptance.
P4 · Cable tray, Zone P1 remaining bays (excl. edge bays)
Patel A · 2 electricians · 48 planned hours
Mon 16 h + Tue 16 h + Wed 16 h = 48 available h through the deadline
- Promiser → recipient
- Patel → S. Ahmed
- Acceptance criteria
- Installed, supported, covers fitted
- Deadline
- Wed 20 Jan, 15:30
- Accepted by S. Ahmed
- Wed 20 Jan, 15:30 · kept
P4 fills this crew’s first three days. Nominal time allocation, not measured productivity. Foremen excluded.
424 planned hours across 10 promises; 96 nominal hours remain unpromised across the crews.
Explore all promises and crew-day allocations
All crews shown
Lee A · promises and available time
Hangers, Zone P2 concourse GL1-4
Lee · Lee A → A. Kowalski
- Accept when
- Rev C positions; QA tag
- Due
- Wed 20 Jan, 15:30
- Acceptance record
- Wed 20 Jan, 15:30 · kept
- Allocation
- Mon 24 h · Tue 24 h · Wed 24 h
Conduit run, Zone P2 GL1-4
Lee · Lee A → M. Clarke
- Accept when
- Supported, bonded; pre-cover request issued
- Due
- Fri 22 Jan, 15:30
- Acceptance record
- Not recorded · missed
- Allocation
- Thu 24 h · Fri 24 h
Size the promise by crew and day
3 electricians · 24 h/day- Mon
- P1 24 h24/24 h
- Tue
- P1 24 h24/24 h
- Wed
- P1 24 h24/24 h
- Thu
- P2 24 h24/24 h
- Fri
- P2 24 h24/24 h
0 unpromised h for this crew
Lee B · promises and available time
Hangers, Zone P2 GL4-8
Lee · Lee B → T. Nguyen
- Accept when
- Rev C positions; QA tag
- Due
- Thu 21 Jan, 15:30
- Acceptance record
- Not recorded · missed
- Allocation
- Mon 24 h · Tue 24 h · Wed 24 h
Joint QA walk, Zone P1 branch conduit (prior week); punch list. Not an authority inspection; not permission to close in
Lee · Lee B → M. Clarke
- Accept when
- Walk done; punch list issued and acknowledged
- Due
- Fri 22 Jan, 11:00
- Acceptance record
- Not recorded · missed
- Allocation
- Fri 4 h
T. Nguyen (4 electrician-hours); Lee excluded
Size the promise by crew and day
3 electricians · 24 h/day- Mon
- P3 24 h24/24 h
- Tue
- P3 24 h24/24 h
- Wed
- P3 24 h24/24 h
- Thu
- Unpromised0/24 h
- Fri
- P10 4 h4/24 h
44 unpromised h for this crew
Patel A · promises and available time
Cable tray, Zone P1 remaining bays (excl. edge bays)
Patel · Patel A → S. Ahmed
- Accept when
- Installed, supported, covers fitted
- Due
- Wed 20 Jan, 15:30
- Acceptance record
- Wed 20 Jan, 15:30 · kept
- Allocation
- Mon 16 h · Tue 16 h · Wed 16 h
Size the promise by crew and day
2 electricians · 16 h/day- Mon
- P4 16 h16/16 h
- Tue
- P4 16 h16/16 h
- Wed
- P4 16 h16/16 h
- Thu
- Unpromised0/16 h
- Fri
- Unpromised0/16 h
32 unpromised h for this crew
Patel B · promises and available time
Cable tray, Zone P2 service corridor
Patel · Patel B → J. Ortiz
- Accept when
- Continuous LP-P2 to riser; bonded
- Due
- Thu 21 Jan, 15:30
- Acceptance record
- Thu 21 Jan, 09:00 · kept
- Allocation
- Mon 16 h · Tue 16 h · Wed 16 h
Tray bonding, Zone P1
Patel · Patel B → D. Moreau
- Accept when
- Continuity tested, recorded
- Due
- Fri 22 Jan, 11:00
- Acceptance record
- Fri 22 Jan, 11:00 · kept
- Allocation
- Thu 16 h · Fri 8 h
Size the promise by crew and day
2 electricians · 16 h/day- Mon
- P5 16 h16/16 h
- Tue
- P5 16 h16/16 h
- Wed
- P5 16 h16/16 h
- Thu
- P6 16 h16/16 h
- Fri
- P6 8 h8/16 h
8 unpromised h for this crew
Okafor · promises and available time
Set + anchor LP-P2 (wall)
Okafor · Okafor → J. Ortiz
- Accept when
- Anchored, level, labelled, ready to terminate
- Due
- Tue 19 Jan, 11:00
- Acceptance record
- Tue 19 Jan, 11:00 · kept
- Allocation
- Mon 24 h · Tue 12 h
Set LP-P3 on housekeeping pad
Okafor · Okafor → J. Ortiz
- Accept when
- Anchored on accepted pad, level
- Due
- Wed 20 Jan, 15:30
- Acceptance record
- Not recorded · missed
- Allocation
- Tue 12 h · Wed 24 h
Pull boxes, Zone P1
Okafor · Okafor → D. Moreau
- Accept when
- Installed, labelled
- Due
- Fri 22 Jan, 11:00
- Acceptance record
- Fri 22 Jan, 11:00 · kept
- Allocation
- Thu 24 h · Fri 12 h
Size the promise by crew and day
3 electricians · 24 h/day- Mon
- P7 24 h24/24 h
- Tue
- P7 12 h + P8 12 h24/24 h
- Wed
- P8 24 h24/24 h
- Thu
- P9 24 h24/24 h
- Fri
- P9 12 h12/24 h
12 unpromised h for this crew
520 nominal h · 424 promised h · 96 unpromised h. Foremen excluded.
Into promise P2
P1 accepted Wed 20 Jan, 15:30 → Thu 21 Jan, 07:00
Into promise P6
P4 accepted Wed 20 Jan, 15:30 → Thu 21 Jan, 07:00
Into promise P9
RS-1: Wed 20 Jan, 15:30 → Thu 21 Jan, 07:00
Explore ready backlog, held work and commitment conditions
Ready, deliberately unpromised
B1 · 60 planned h
Lighting fixture pre-assembly, laydown
B2 · 40 planned h
Zone P3 concourse hanger floor marking (work for week of 1 Feb)
B3 · 48 planned h
Zone P3 corridor tray bracket pre-fabrication, laydown
‖ F-P2 pull · constrained (C-015)
‖ Zone P1 edge-bay tray · held back (C-021)
The commitment has a customer
A scope.
A recipient.
A due time.
An acceptance test.
424 planned hours across 10 promises. 96 nominal hours remain unpromised; they belong to specific crews.
Native grid alternate: DS-5 crew allocations · DS-6 full promise ledger
DS-5 Planned and actual crew time Inspect the records
| Crew / basis | Mon | Tue | Wed | Thu | Fri | Total |
|---|---|---|---|---|---|---|
| Lee A — planned | P1 24 h | P1 24 h | P1 24 h | P2 24 h | P2 24 h | 120 h |
| Lee A — actual | P1 24 h | P1 24 h | P1 24 h | P2 24 h | P2 8 h + reassigned 16 h | 120 h |
| Lee B — planned | P3 24 h | P3 24 h | P3 24 h | Unpromised | P10 4 h | 76 h |
| Lee B — actual | B1 24 h | B1 24 h | B1 12 h + P3 12 h | P3 24 h | P3 24 h | 120 h |
| Patel A — planned | P4 16 h | P4 16 h | P4 16 h | Unpromised | Unpromised | 48 h |
| Patel A — actual | P4 16 h | P4 16 h | P4 16 h | B3 16 h | B3 16 h | 80 h |
| Patel B — planned | P5 16 h | P5 16 h | P5 16 h | P6 16 h | P6 8 h | 72 h |
| Patel B — actual | P5 16 h | P5 16 h | P5 16 h | P6 16 h | P6 8 h + B3 8 h | 80 h |
| Okafor — planned | P7 24 h | P7 12 h + P8 12 h | P8 24 h | P9 24 h | P9 12 h | 108 h |
| Okafor — actual | P7 24 h | P7 12 h + B2 12 h | B2 24 h | P9 24 h | P9 12 h + B2 4 h + receiving 8 h | 120 h |
DS-6 Ten-promise ledger Inspect the records
| Promise / scope | Promiser → recipient | Acceptance criterion | Due / planned | Accepted / result | Later record |
|---|---|---|---|---|---|
| Promise P1: Hangers, Zone P2 concourse GL1-4 | Lee (Lee A) → A. Kowalski | Rev C positions; QA tag | Wed 20 Jan, 15:30; 72 h | Wed 20 Jan, 15:30; kept | — |
| Promise P2: Conduit run, Zone P2 GL1-4 | Lee (Lee A) → M. Clarke | Supported, bonded; pre-cover request issued | Fri 22 Jan, 15:30; 48 h | Not recorded; missed | Physical completion Mon 25 Jan, 11:00 · 1 working date late (4 working hours). Acceptance not recorded. |
| Promise P3: Hangers, Zone P2 GL4-8 | Lee (Lee B) → T. Nguyen | Rev C positions; QA tag | Thu 21 Jan, 15:30; 72 h | Not recorded; missed | Physical completion Mon 25 Jan, 11:00 · 2 working dates late (12 working hours). Acceptance not recorded. |
| Promise P4: Cable tray, Zone P1 remaining bays (excl. edge bays) | Patel (Patel A) → S. Ahmed | Installed, supported, covers fitted | Wed 20 Jan, 15:30; 48 h | Wed 20 Jan, 15:30; kept | — |
| Promise P5: Cable tray, Zone P2 service corridor | Patel (Patel B) → J. Ortiz | Continuous LP-P2 to riser; bonded | Thu 21 Jan, 15:30; 48 h | Thu 21 Jan, 09:00; kept | — |
| Promise P6: Tray bonding, Zone P1 | Patel (Patel B) → D. Moreau | Continuity tested, recorded | Fri 22 Jan, 11:00; 24 h | Fri 22 Jan, 11:00; kept | — |
| Promise P7: Set + anchor LP-P2 (wall) | Okafor (Okafor) → J. Ortiz | Anchored, level, labelled, ready to terminate | Tue 19 Jan, 11:00; 36 h | Tue 19 Jan, 11:00; kept | — |
| Promise P8: Set LP-P3 on housekeeping pad | Okafor (Okafor) → J. Ortiz | Anchored on accepted pad, level | Wed 20 Jan, 15:30; 36 h | Not recorded; missed | Pad pour rescheduled 2027-01-27; acceptance for anchoring TBC |
| Promise P9: Pull boxes, Zone P1 | Okafor (Okafor) → D. Moreau | Installed, labelled | Fri 22 Jan, 11:00; 36 h | Fri 22 Jan, 11:00; kept | — |
| Promise P10: Joint QA walk, Zone P1 branch conduit (prior week); punch list. Not an authority inspection; not permission to close in | Lee (Lee B) → M. Clarke | Walk done; punch list issued and acknowledged | Fri 22 Jan, 11:00; 4 h | Not recorded; missed | Rebooked 2027-01-26T07:00 |
The right to say no
Ballard and Tommelein call it “an essential prerequisite for reliable promising” that suppliers can say no by appeal to sequence or readiness, including size relative to capacity (2021, p. 8). A foreman who can only say yes isn’t making a promise. If management wants more committed than the field will promise, the gap is information to act on.
Is a one-week list a Weekly Work Plan?
Covering one week doesn’t make a plan a Weekly Work Plan in the Last Planner sense, and being written by the GC doesn’t disqualify it. What matters is where the commitments come from. Five questions work as a diagnostic, not a certification:
- Did the tasks come from work assessed as ready, rather than straight from schedule dates?
- Does each task have a named promiser who does the work or directs the crew that does?
- Could that person have declined or changed the task?
- Is each task defined, sound, sequenced and sized to the crew, day by day?
- Does each name an accountable recipient, acceptance criteria and a due time?
A GC-compiled plan that records promises trades made in the room can pass all five. A list exported from schedule dates may pass none. Whether the promises were kept is the next section.
7. DID: the week
The week starts with ten promises and ends with a record of which were kept. In between sits early warning. Ballard and Tommelein make it a principle: “Make and secure reliable promises, and speak up immediately should you lose confidence that you can keep your promises” (2021, p. 10). On Riverside the foremen use a short daily huddle; that format is a scenario choice, while the warning is the principle.
How the week unfolds
- Mon 07:15. The second scissor lift hasn’t arrived. Lee flags promise P3 at risk and tells its recipient, T. Nguyen. Crew B switches to backlog B1 (lighting pre-assembly), which needs no lift. The superintendent chases the supplier.
- Mon 08:30. Walking the LP-P3 area, Okafor finds the housekeeping pad formed but not poured. He tells the GC superintendent, M. Clarke, that promise P8 (due Wednesday) can’t be met; notice to the promise’s recipient, J. Ortiz, is not recorded. From Tuesday afternoon his crew moves to backlog B2 (Zone P3 floor marking).
- Wed 11:30. The lift arrives. Crew B, having finished B1 at 11:00, starts promise P3 after the break.
- Thu 15:30. Promise P3 falls due. The foreman’s quantity check: hangers complete GL4–6 of GL4–8. Not kept.
- Thu 16:00. M. Clarke moves Friday’s Zone P1 QA walk (promise P10) to Tuesday 26 January, 07:00, because of an authority meeting.
- Fri 07:00. The PM reassigns two of crew A’s three electricians to an emergency fault outside the platform area. At 07:15 Lee tells M. Clarke that promise P2 is at risk.
Synthetic example
A promise survives its deadline
Final-week result
6 of 10 promises kept.Final PPC = 60%.
Accepted by the original due time. All ten original promises remain in the final denominator.
P3 · a warning, a miss, then recovery
- Original commitmentHangers, Zone P2 GL4-8 → T. Nguyen; Rev C positions; QA tag. Due Thu 21 Jan, 15:30.
- Early warning · Mon 18 Jan, 07:15Lift-2 absent; P3 at risk; T. Nguyen told; Lee B to B1
- At the deadline · missedGL4-6 complete (foreman quantity check). Acceptance not recorded.
- Later recoveryPhysical completion Mon 25 Jan, 11:00 · 2 working dates late (12 working hours). Acceptance not recorded. The original miss remains.
Learning and follow-up · P3
Reason classification: change after commitment + contributing screening weakness (hypothesis).
Proposed countermeasure: Verify equipment availability for the work period, or a confirmed usable backup.
Superintendent · review Fri 29 Jan → effectiveness check Fri 19 Feb. Effectiveness not yet checked.
Explore daily states, acceptance and warning records
Selected day · Fri 22 Jan · calendar-day end
Final weekly PPC
6/10 = 60%Accepted by the original due timeSpeak up when confidence changes
- Commitment meeting; F-P2 cable delay escalated to GC
- Lift-2 absent; P3 at risk; T. Nguyen told; Lee B to B1
- Pad not poured; P8 won't be met; M. Clarke (prerequisite owner) notified; notice to recipient J. Ortiz not recorded
- Lift-2 arrives; Lee B starts P3
- GC moves P10 walk to Tue 26 Jan 07:00
- Two Lee A electricians reassigned
- P2 at risk; M. Clarke told
Explore later recovery and full-week work outside promises
Recovery does not rewrite the promise
Follow-up after the original deadlines · not a state at the selected day.
Promise P2 — Physical completion Mon 25 Jan, 11:00 · 1 working date late (4 working hours). Acceptance not recorded.
Promise P3 — Physical completion Mon 25 Jan, 11:00 · 2 working dates late (12 working hours). Acceptance not recorded.
Promise P8 — Pad pour rescheduled 2027-01-27; acceptance for anchoring TBC
Promise P10 — Rebooked 2027-01-26T07:00
Work outside the original promises
Full-week record · outside both the PPC numerator and denominator.
Explore all countermeasures and follow-up dates
A miss becomes a proposed change
Proposed countermeasures; effectiveness not yet checked.
Promise P8 · screening failure
Verify the prerequisite against acceptance conditions; obtain pad-acceptance evidence.
Superintendent
Review Fri 29 Jan → effectiveness check Fri 19 Feb
Promise P3 · change after commitment + contributing screening weakness (hypothesis)
Verify equipment availability for the work period, or a confirmed usable backup.
Superintendent
Review Fri 29 Jan → effectiveness check Fri 19 Feb
Promise P2 · change after commitment
Discuss reassignment with the foreman first; notify the recipient immediately on loss of confidence.
PM
Review Fri 29 Jan → effectiveness check Fri 19 Feb
Promise P10 · change by receiving party
Reconfirm the joint walk; agree an authorised fallback; notify affected parties on change.
Lee, with GC
Review Fri 29 Jan → effectiveness check Fri 19 Feb
Full records: DS-6 promises · DS-7 daily states · DS-8 learning
Scoring at the promised time
A promise is kept only if the work is complete and accepted by its recipient at the due time. Later recovery is recorded beside the miss, not used to erase it.
Six promises were kept: P1, P4, P5, P6, P7 and P9. Promise P5, for example, was finished on Wednesday and accepted by J. Ortiz at 09:00 Thursday, ahead of its 15:30 due time. Four were not kept:
- Promise P2 — three of four conduit runs done at the Friday deadline; complete Monday 25 January, 11:00. One working day late.
- Promise P3 — GL4–6 done at the Thursday deadline, GL4–7 by Friday; complete Monday 25 January, 11:00. Two working days late.
- Promise P8 — not started. The GC reschedules the pad pour to Wednesday 27 January; the date it is accepted for anchoring is still to be confirmed.
- Promise P10 — moved by the recipient; rebooked for Tuesday 26 January.
The progress notes are the foreman’s quantity checks, not percentages derived from hours. “Working days late” counts working dates: in elapsed working time, promise P2 finished four hours after its deadline and promise P3 twelve. Neither late completion has a recorded acceptance.
Work outside the promises
The crews’ time is recorded separately from the promises, so nothing is counted twice. Crew B spent 60 hours on backlog B1 (complete) while the lift was missing. Okafor’s crew spent 40 hours on backlog B2 (complete), 36 of them in the time promise P8 had been planned to use. Patel’s crews charged 40 hours of planned spare capacity to backlog B3 against an original 48-hour estimate. B3 is reported partially complete; its remaining work isn’t recorded here, and it can’t be calculated by subtracting hours spent from the estimate. The two reassigned electricians spent 16 hours off the platform, and Okafor’s crew spent 8 hours receiving material. None of this enters PPC.
DS-7 Daily states & events Inspect the records
| Promise / event | Mon | Tue | Wed | Thu | Fri |
|---|---|---|---|---|---|
| Promise P1 | in progress | in progress | accepted 15:30 | accepted | accepted |
| Promise P2 | planned Thu | planned Thu | released | in progress | missed at due |
| Promise P3 | at risk | at risk | in progress | missed at due | missed; in progress after due |
| Promise P4 | in progress | in progress | accepted 15:30 | accepted | accepted |
| Promise P5 | in progress | in progress | complete, awaiting acceptance | accepted 09:00 | accepted |
| Promise P6 | waiting for P4 | waiting for P4 | released | in progress | accepted 11:00 |
| Promise P7 | in progress | accepted 11:00 | accepted | accepted | accepted |
| Promise P8 | won't be met (08:30) | blocked | missed at due | missed | missed |
| Promise P9 | planned Thu | planned Thu | released | in progress | accepted 11:00 |
| Promise P10 | not yet due | not yet due | not yet due | moved by recipient (16:00) | missed at due |
| Due-to-date PPC | No promises due | 1/1 = 100% | 3/4 = 75% | 4/6 = 66.7% | 6/10 = 60% |
| Fri 15 Jan | — | — | — | — | — |
| Mon 18 Jan, 07:15 | Lift-2 absent; P3 at risk; T. Nguyen told; Lee B to B1 | — | — | — | — |
| Mon 18 Jan, 08:30 | Pad not poured; P8 won't be met; M. Clarke (prerequisite owner) notified; notice to recipient J. Ortiz not recorded | — | — | — | — |
| Wed 20 Jan, 11:30 | — | — | Lift-2 arrives; Lee B starts P3 | — | — |
| Thu 21 Jan, 16:00 | — | — | — | GC moves P10 walk to Tue 26 Jan 07:00 | — |
| Fri 22 Jan, 07:00 | — | — | — | — | Two Lee A electricians reassigned |
| Fri 22 Jan, 07:15 | — | — | — | — | P2 at risk; M. Clarke told |
8. PPC: what it measures
Percent Plan Complete is the number of promises completed and accepted as promised, divided by the number of promises made.
Weighting by hours is a natural controls instinct. The six kept promises carried 72 + 48 + 48 + 24 + 36 + 36 = 264 of the 424 planned hours promised:
The label is long on purpose. 264 is planned weight, not hours worked, productivity or physical progress. The 160 planned hours on the four missed promises aren’t 160 hours still to do; promises P2 and P3 were well advanced. PPC doesn’t weight by hours because it measures how reliable the promises were.
The 140 hours of backlog work (B1 60, B2 40, B3 40) sit outside both numerator and denominator. They weren’t promised, so they can’t be kept or broken. El Samad, Hamzeh and Emdanat likewise treat work outside the original commitments separately from PPC (2017, p. 641).
PPC is a weekly figure. During the week, the only fair running figure counts promises already due. By Wednesday evening that is 3 of 4; the final figure is 6 of 10. Promises not yet due are never shown as misses.
Return to V6: the week, PPC and learning.
Reliability is not schedule performance
PPC shows how reliable promises were. It doesn’t show whether the right work was promised, or enough of it, so it can’t stand in for physical progress, productivity, schedule performance, critical-path advancement or cost. Ballard and Tommelein put it this way: “it also became apparent that PPC could be 100%, productivity excellent, and a project still be falling behind schedule” (2021, p. 3). Their response was to add a lookahead process, so that what SHOULD be done CAN be done when needed.
Riverside shows the point at small scale: the week’s largest risk, the F-P2 cable, was never promised and never touched PPC.
Ballard and Howell advise that “emphasis should be placed on the direction and rate of change in PPC rather than on its absolute level” (2003). That doesn’t license ignoring a low number. Read the trend alongside the specific misses and what they cost.
Source note. Hamzeh, Ballard and Tommelein (2012) report weak correlations between PPC and negative incremental schedule difference, a measure of schedule gain or slip against the master schedule: 0.28 on a hospital project (pp. 21–22) and 0.13 on a rehabilitation and new-construction project (p. 23). These are two case studies, not a general coefficient.
9. LEARN: from reasons to countermeasures
A missed promise is useful only if it changes how the next plan is made. The question that separates the lessons is: what was the readiness evidence at the moment of commitment?
Promise P8 — screening failure. The pad was assessed ready from a report that it was poured. Nobody checked it against the panel’s acceptance condition, anchoring on an accepted pad. The work wasn’t ready when promised.
Promise P3 — change after commitment, with a contributing screening weakness. The supplier delivered the lift on Wednesday at 11:30 instead of Monday at 07:00. The constraint had been cleared on a written booking, not on a lift available in the zone.
Promise P2 — change after commitment. The work was ready and staffed when promised. A management decision on Friday morning removed two of the three electricians.
Promise P10 — change by the receiving party. The walk was booked a week ahead; the GC moved it the afternoon before.
Screening failures call for a better screen, changes after commitment for better protection of promises and faster notice, and receiving-party changes for better coordination.
One 5-whys, held as a hypothesis
Ballard and Howell recommend the 5 whys to reach causes that can be acted on. For promise P3:
- Why was promise P3 missed? The second lift wasn’t on site Monday.
- Why not? The supplier missed the delivery.
- Why did that stop the work? We had a booking, not a lift.
- Why was the work released on a booking? The constraint log allowed “confirmed booking” to count as cleared.
- Why? The clearance rule didn’t distinguish a supplier’s commitment from equipment available for the work period.
The booking rule is a contributing-cause hypothesis to test. It doesn’t explain why the supplier was late.
Proposed countermeasures
- Promise P8: verify the prerequisite against the task’s acceptance conditions before commitment. A walk or dated photograph can confirm visible status; obtain the additional evidence needed for pad and anchoring readiness. Reconfirm if conditions change before release. Owner: superintendent.
- Promise P3: verify equipment availability for the required work period, or a confirmed usable backup, before treating an equipment constraint as cleared. Owner: superintendent.
- Promise P2: discuss a proposed reassignment with the responsible foreman before changing the committed crew. Notify the recipient as soon as confidence in the promise is lost, and agree the response. Owner: PM.
- Promise P10: reconfirm the joint walk and agree an authorised fallback where possible. If the recipient’s availability changes, notify affected parties immediately and assess the handoff consequence. Reconfirmation alone doesn’t prevent cancellation. Owner: Lee, with the GC superintendent.
Each is first reviewed at the weekly planning meeting on Friday 29 January, with an effectiveness check at the lookahead review on Friday 19 February. These are proposed countermeasures for a synthetic example. Their effectiveness has to be checked at those reviews; no improvement is claimed here.
Return to V6: the week, PPC and learning.
DS-8 Countermeasures & reviews Inspect the records
| Promise | Classification | Proposed countermeasure | Owner | Review / effectiveness check |
|---|---|---|---|---|
| Promise P8 | screening failure | Verify the prerequisite against acceptance conditions; obtain pad-acceptance evidence. | Superintendent | Fri 29 Jan / Fri 19 Feb |
| Promise P3 | change after commitment + contributing screening weakness (hypothesis) | Verify equipment availability for the work period, or a confirmed usable backup. | Superintendent | Fri 29 Jan / Fri 19 Feb |
| Promise P2 | change after commitment | Discuss reassignment with the foreman first; notify the recipient immediately on loss of confidence. | PM | Fri 29 Jan / Fri 19 Feb |
| Promise P10 | change by receiving party | Reconfirm the joint walk; agree an authorised fallback; notify affected parties on change. | Lee, with GC | Fri 29 Jan / Fri 19 Feb |
Learning also flows back to the lookahead. Researchers have proposed measures of lookahead health, such as the share of tasks anticipated in time and the share actually made ready (Hamzeh et al. 2012; El Samad et al. 2017). They answer a question PPC can’t: is CAN producing enough ready work, early enough?
10. The artifact test
Ballard and Tommelein write that “LPS is a system of interconnected parts. Omission of a part destroys the system’s ability to accomplish its functions” (2021, p. 6). The Zone P2 walk shows each conversation producing something the next depends on: handoffs feed the screen, the screen feeds the backlog, the backlog feeds the promises, and the misses feed the countermeasures.
The practical consequence, which is my reading rather than a quoted finding, is that an artifact can exist without the conversation that should produce it. The table turns that into questions. The last column applies to every row: an artifact never settles the matter either way.
| Artifact | Conversation behind it | Evidence to look for | Symmetry note |
|---|---|---|---|
| Pull-plan wall | SHOULD: backward planning, handoff requests and answers between performers | Were the performers in the room? Were handoffs requests with times? Is the plan revisited? | A neat wall doesn't prove it; a messy one doesn't disprove it |
| Lookahead | CAN: breakdown, screening, operation design | Are operations broken down and screened? Is some work held back? | A filtered schedule may be screened elsewhere |
| Constraint log | Make-ready tied to work, need dates and evidence | Does constraint status decide what is released? | A thin log may sit beside strong make-ready |
| One-week plan | WILL: promises from ready work | The five questions in section 6 | A GC-written plan can hold real promises |
| PPC chart | DID and LEARN | Are misses classified by readiness at commitment? Do countermeasures have owners and reviews? | Follow-up may happen off the chart |
11. Back to the schedule and the forecast
Where the master schedule, labour forecast and weekly production planning are managed by different people or systems, their responsibilities and information routes need to be explicit. I use two overlapping lanes to discuss that coordination, weekly production control and periodic project controls; this is a practitioner lens, not a boundary prescribed by the literature.
The question for the overlap is which readiness information should reach the schedule and forecast, and how fast. These review questions are asked together, not as gates in a series:
- Does it change a control date, an interface, a milestone or a driver?
- Does it change the timing or amount of remaining labour enough to matter for staffing?
- Is it a one-off event or a pattern?
- Can make-ready resolve it inside the lookahead window?
- Does the project manager need to decide something now?
None has a universal numerical threshold. Materiality, persistence and timing are project decisions.
The Riverside week, routed
| Information | Route | Basis |
|---|---|---|
| F-P2 cable ETA moves from Mon 25 Jan to Tue 2 Feb (known Fri 15 Jan). Keeping the 2-day preparation: pull Thu 4 – Tue 9 Feb, test Wed 10 Feb. The 3-day delivery float is used up, and 3 of the 4 interface-protection days before the 12 Feb inspection are used; Thu 11 Feb remains | Escalated to the GC at the 15 Jan meeting; PM expedites supply and evaluates pre-staging pulling equipment in the week of 25 Jan, which would cut preparation to 1 day and leave 2 days | Material risk at an interface ahead of a fixed external utility date |
| Same item: feeder-crew hours start Thu 4 Feb instead of Mon 1 Feb | Once the revised window is agreed, review the timing of feeder-crew hours under the normal forecasting process | A later window does not by itself establish a change in total remaining hours |
| Promise P2 finished one working day after its Friday deadline | Stays in production control | Its recipient's next step, the Zone P2 pre-cover inspection, is planned for Tue 9 Feb |
| Promise P3 finished two working days after its Thursday deadline | Stays in production control | Physical completion is reported at 11:00 on Mon 25 Jan; the successor conduit start is reported at 11:30 instead of 07:00. Acceptance before that release and the effect on next week's commitments are not recorded, so absorption of the delay has not been established; reviewed at the Fri 29 Jan weekly planning |
| LP-P3 pad delay | Signalled to the GC; compare the revised accepted-pad date with F-P3's required release (LP-P3 accepted by Fri 5 Feb for a pull in the week of 8 Feb) | Pour rescheduled to Wed 27 Jan; acceptance-for-anchoring date not yet confirmed, so a control-date consequence has not been established |
| Final weekly PPC of 60% | Stays in production control; read with trend and misses | One week's PPC doesn't change a forecast on its own |
PC-I coordination lens
Which signal needs which conversation?
Weekly production control
Readiness · promises · warnings · acceptance · learning
Control date? Interface? Labour timing? Recurring pattern? Decision needed now?
Periodic project controls
Control schedule · remaining labour · staffing · forecast review
The benchmark includes project-control functions within LPS (Ballard and Tommelein 2021, p. 4). Responsibilities in the overlap are project-defined.
↗ Escalate
F-P2 cable delay
3-day float + 3 of 4 interface days used; Thu 11 Feb remains; fixed utility window
Route: immediate escalation (15 Jan)
→ Routine review
Feeder-crew hours start Thu 4 Feb
Timing change; total remaining hours not established as changed
Route: routine forecast review
↔ Production / interface review
P2 late (1 working date)
Pre-cover inspection planned Tue 9 Feb
Route: production control
↔ Production / interface review
P3 late (2 working dates)
Acceptance and next-week effect not recorded; absorption not established
Route: production control; review 29 Jan
↔ Production / interface review
LP-P3 pad
Compare accepted-pad date with 5 Feb F-P3 release; consequence not established
Route: signal to GC
↔ Production / interface review
Final weekly PPC 60%
Read with trend and misses
Route: production control
Native route table: DS-9
DS-9 Routes to project controls Inspect the records
| Information | Route | Basis |
|---|---|---|
| F-P2 cable delay | immediate escalation (15 Jan) | 3-day float + 3 of 4 interface days used; Thu 11 Feb remains; fixed utility window |
| Feeder-crew hours start Thu 4 Feb | routine forecast review | Timing change; total remaining hours not established as changed |
| P2 late (1 working date) | production control | Pre-cover inspection planned Tue 9 Feb |
| P3 late (2 working dates) | production control; review 29 Jan | Acceptance and next-week effect not recorded; absorption not established |
| LP-P3 pad | signal to GC | Compare accepted-pad date with 5 Feb F-P3 release; consequence not established |
| Final weekly PPC 60% | production control | Read with trend and misses |
Make-ready and commitment discussions can produce information that the schedule and forecast need. The project must define how that information reaches the people who review dates and remaining labour, including any routes already used outside these discussions.
12. Close: a better question
The starting point was a project with all the pieces: a pull plan, a lookahead, a constraint report and a weekly plan. The question was whether that meant we were doing Last Planner.
Following Zone P2 suggests the question sits at the wrong level. The more useful one is: which of the five conversations are we having, and what does each one hand on? Is the phase plan made by the people who’ll do the work, as requests with times? Is the lookahead screened on evidence, with some work deliberately held back? Does constraint status decide what gets released? Are weekly commitments real promises, sized crew by crew and day by day, with an accountable recipient? Do misses lead to countermeasures that someone reviews later?
On Riverside, some conversations held and some showed weak spots: a screen that accepted a report and a booking as evidence, and a promise broken by a reassignment no one discussed with the foreman first. The value lies in seeing which conversation failed, so the next plan can be better.
For project controls, the bridge is modest. When the conversations happen, they produce readiness information that the schedule and the forecast can review, sometimes immediately and sometimes at the next update. How a project builds that bridge is its own decision.
References
- Ballard, G. (2000). The Last Planner System of Production Control. PhD thesis, University of Birmingham. Original thesis
- Ballard, G. and Howell, G. A. (2003). “An Update on Last Planner.” 11th Annual Conference of the International Group for Lean Construction, Virginia, USA. Conference record · PDF. Cited by section or PDF page position.
- Ballard, G. and Tommelein, I. D. (2021). 2020 Current Process Benchmark for the Last Planner System of Project Planning and Control. P2SL, University of California, Berkeley, March 2021, version 2. PDF
- El Samad, G., Hamzeh, F. and Emdanat, S. (2017). “Last Planner System – The Need for New Metrics.” 25th Annual Conference of the International Group for Lean Construction, Heraklion, Greece, 637–644. DOI: 10.24928/2017/0218. Conference record
- Hamzeh, F. R., Ballard, G. and Tommelein, I. D. (2012). “Rethinking Lookahead Planning to Optimize Construction Workflow.” Lean Construction Journal, 15–34. Publisher record
- Lean Construction Institute. “Last Planner System.” Overview
DS-10 Computed checks Inspect the records
| Check | Computed result |
|---|---|
| Nominal electrician-hours | 520 |
| Promised planned hours | 424 |
| Unpromised nominal hours | 96 |
| Promises kept | 6 |
| Promises made | 10 |
| Planned hours on kept promises | 264 |
| Planned hours on missed promises | 160 |
| Final PPC (%) | 60 |
| Planned-hour ratio (%) | 62.3 |
| Planned / nominal (%) | 81.5 |
| Actual time on promised work | 356 |
| Actual backlog time | 140 |
| Actual reassigned time | 16 |
| Actual receiving time | 8 |
| Total actual time | 520 |