Percent Plan Complete (PPC) and Reasons for Variance

Percent Plan Complete is the share of weekly commitments that were fully completed as promised. It's a simple number, and that's the point: it measures how reliable your short-term planning is. This post covers how to calculate it without fudging, how to record reasons for variance so they're worth reading, and the ways PPC gets misread.

The calculation

PPC comes from the weekly work plan in the Last Planner System. Each trade commits to specific tasks for the week. At the end of the week, each commitment is marked complete or not complete. Then:

PPC = commitments completed / commitments made

The rules that keep the number honest:

• Binary. A task is either 100% done as defined or it isn't. A task that's 90% done counts as not complete. No partial credit.
• As promised. Done means done within the week, at the scope committed. If the commitment was rooms 301-306 and the crew finished 301-305 plus 307, that's not complete.
• Count commitments, not hours or dollars. Each commitment counts once, whether it's a two-hour inspection or a five-day pour sequence. That's a weakness when tasks vary a lot in size, which is one reason good commitments are sized to fit a week.
• Only commitments. Work done that wasn't on the plan doesn't raise PPC. Track it separately if you want to know about it.

A worked week

A mid-rise job, week 22, interiors on levels 2 and 3:

Commitments made:      12
Commitments completed:  8
PPC = 8 / 12 = 66.7%

You can also compute PPC by trade. Here, plumbing and fire protection hit 100%, drywall came in at 2 of 3 (67%), electrical and mechanical at 1 of 2 (50%), and the GC's own commitments came in at 50%. GC misses deserve as much attention as trade misses; they often cause the trade misses the following week.

Reasons for variance

The number tells you how reliable the plan was. The reasons tell you why. Without reasons, PPC is a scoreboard. With them, it's a diagnostic.

Pick a short, fixed list of categories and use it every week so you can compare over time. A typical list:

Keep it under a dozen. If people pick "Other" more than occasionally, the list is missing a category.

Record a one-line description with every miss. "Material" alone doesn't help. "Panels delivered with wrong bus rating, submittal was approved correctly, supplier error" tells you whether the fix is with the supplier or with your own submittal review.

Reading the reasons over time

After six or eight weeks, tally the reasons and sort them. The top two or three categories usually account for most of the misses. That's where to spend effort.

• If prerequisite work dominates, the lookahead isn't screening handoffs well. Trades are committing to work that depends on someone else's unfinished task.
• If design / information dominates, the constraint log isn't catching RFIs and submittals early enough. See make-ready planning and constraint logs.
• If planning dominates, commitments are too big or too vague. Coach on commitment quality: specific, sound, sized to the crew.
• If manpower dominates, the subcontractor may be overcommitted across jobs. That's a conversation for the PM, not the weekly meeting.

For the recurring ones, ask "why" a few times. Failed in-wall inspection: why? The electrician missed nail plates. Why? The crew was new to the job and didn't get the site-specific checklist. That's a fix you can make once.

What PPC doesn't tell you

PPC is not schedule progress

A team can run 90% PPC and still fall behind the master schedule, because PPC measures whether you did what you planned, not whether what you planned was enough. If every trade commits to half of what the CPM needs, and completes it all, PPC is 100% and the job is slipping.

Check weekly commitments against what the lookahead and the CPM require. If critical-path work isn't getting committed, find out why. PPC and schedule variance analysis answer different questions, and you need both.

PPC can be gamed

The easiest way to raise PPC is to commit to less. If PPC is used to grade subcontractors, expect sandbagging. Use it to find problems in the planning system, not to punish people. Watch for trades whose PPC is always perfect but whose commitments are suspiciously small.

Small samples bounce around

A trade with two commitments a week will show 0%, 50%, or 100%. Don't overreact to one week. Look at a rolling four-week average, and at the project-wide number, which has more commitments behind it.

Using PPC in the weekly meeting

A practical rhythm:

1. Review last week's commitments, trade by trade. Mark each done or not done. Record the reason for every miss on the spot, while the people who know are in the room.
2. Post the week's PPC and the rolling trend.
3. Spend a few minutes on the top recurring reason. Assign one corrective action with an owner.
4. Move to next week's commitments, drawn from screened lookahead work.

Keep the review short and factual. The goal isn't to make anyone feel bad; it's to learn where the plan breaks. Running weekly meetings off the schedule has more on keeping that meeting tied to the CPM.

Tracking this in a spreadsheet works. If you'd rather not maintain one, schedule.construction's weekly work plans calculate PPC and keep the reasons for variance with each commitment.

Key takeaways

• PPC = commitments completed / commitments made. Binary, no partial credit, only planned commitments count.
• Record a reason category and a one-line description for every miss, using a short fixed list.
• After several weeks, sort the reasons. Fix the top two or three at the root.
• High PPC doesn't mean the job is on schedule. Check commitments against what the CPM needs.
• Use PPC to improve the planning system, not to grade subcontractors, or it will get gamed.