Short answer: Percent Plan Complete, or PPC, is the share of tasks your crews promised to finish this week that they actually finished. Count the promises on Monday, count the finished ones on Friday, and write down why each miss happened. The reasons matter more than the number.
What is Percent Plan Complete?
PPC comes from the Last Planner System, a lean way of planning site work with the people who do it. The idea is simple. Each week the foreman or crew lead commits to a short list of tasks. At the end of the week you divide the tasks completed by the tasks committed.
If your AC crew promised ten tasks and finished seven, your PPC is 70 percent. A task half done counts as not done. That rule feels harsh, but it is the point. The next trade cannot start on a half finished first fix.
What is a good PPC score?
Most teams score lower than they expect. A 2023 review of 36 published PPC studies from 1998 to 2021 found the average was about 71 percent, with no real improvement over two decades (IGLC review of PPC studies). The same review notes that 80 percent is usually called good and under 60 percent poor.
The score also tracks how a job ends. In a study of Chilean projects, successful ones averaged 76 percent PPC against 61 percent for the ones that struggled, and their weekly scores swung less (Alarcón and others, IGLC). On two Irish projects, trade averages ranged from 72 to 92 percent, and the trades used to planning this way scored highest (IGLC trade study).
So do not chase 100 percent. A crew hitting 100 every week is probably promising too little. Aim for a steady 80 and fewer surprises.
How do you work it out each week?
- Monday: write the commitments. Only tasks that are ready, meaning materials on site, access agreed and the previous trade done. Each task gets one owner.
- Friday: mark each task done or not done. No partial credit.
- Divide. Done tasks over committed tasks, times 100.
- Write one reason for every miss. Keep the reasons to a short fixed list so you can count them.
- Plot the weekly number. One point a week is enough. The trend tells you more than any single week.
Which reasons for a miss come up most?
On small jobs the same few causes repeat. Track them like this:
| Reason for the miss | What it usually means | Fix for next week |
|---|---|---|
| Materials not on site | Order placed too late | Check lead times three weeks out |
| Waiting on a decision | Client or designer answer late | Give the question a decision date |
| Previous trade not finished | Handover not planned | Link the two tasks |
| Crew moved to another job | Promised the same people twice | Plan all jobs on one view |
| Weather or access | Not checked before committing | Check before Monday |
Most misses trace back to work that was never really ready. Our 3-week lookahead guide shows how to clear those blocks before a task reaches the weekly list, and our RFI and decision dates guide covers the answers you wait on.
A small example
A solar installer runs three rooftop jobs with two crews. In week one the crews commit to 14 tasks and finish 8, a PPC of 57 percent. Four of the six misses say the same thing: crew moved to another job. The owner had promised one crew to two roofs on the same days.
In week two every job sits on one plan, each task has one named crew, and nobody commits a crew twice. They promise 11 tasks and finish 9, a PPC of 82 percent. The crews did not work harder. The plan got honest. Our guide to scheduling multiple solar jobs covers that setup.
Where Zace fits
Zace is a project and task tracker for construction, AC and solar jobs and the office work around them. You can put each week's committed tasks on the Gantt chart, assign every task to one crew lead with a priority, link tasks so a late handover shows its knock on effect, and mark key dates as milestones. When a task misses, move it on the timeline and everyone sees the new plan. It runs on the web, Android and iOS, so a crew lead on the roof sees the same week as the office.
Frequently asked questions
Is PPC only for big lean projects?
No. A two crew contractor can run it on one page. You only need the Monday list and the Friday count.
Should PPC be used to rate crews?
Use it to find causes, not to blame people. If crews get punished for misses, they start promising less and the score stops meaning anything.
How long before PPC improves?
Expect a few weeks. Track the reasons for misses, fix the most common one first, and the number usually moves within a month.
Sources (all linked inline): IGLC quantitative review of PPC studies (2023); Alarcón and others, Using Last Planner indicators to identify early signs of project performance; IGLC study of individual trade PPC on two Irish projects.