Why rules of credit matter
Without agreed rules, percent complete becomes an opinion. A supervisor may report a pipe spool as 80% complete because it is hanging in place, while the client sees an unwelded, untested line. Rules of credit fix this by splitting each type of work into measurable steps, each with a fixed share of the activity's weight. They are normally written into the project's progress measurement procedure and agreed with the client before work starts.
Measurement methods
| Method | How progress is earned | Good for |
|---|---|---|
| Units completed | Quantity done ÷ scope quantity | Repetitive work: welds, cable metres, cubic metres of concrete |
| Weighted steps (milestones) | Fixed percentage when each step is finished | Work with distinct stages: equipment, piping systems, drawings |
| 0/100 | Nothing until complete | Very short activities, under one reporting period |
| 50/50 | Half at start, half at finish | Short activities spanning two periods |
| Level of effort | Progress follows elapsed time | Support work: supervision, project management |
| Supervisor's estimate | Judgement | Last resort, small items only |
Example credit steps by discipline
Civil: concrete foundations
| Step | Credit |
|---|---|
| Excavation and blinding | 10% |
| Formwork | 20% |
| Reinforcement and embedded items | 25% |
| Concrete poured | 35% |
| Strip, cure and backfill | 10% |
Structural steel (per tonne)
| Step | Credit |
|---|---|
| Shake-out and pre-assembly | 10% |
| Erected | 50% |
| Aligned and plumbed | 15% |
| Bolted up and torqued | 20% |
| Touch-up painting and punch list | 5% |
Piping (per test pack or line, weighted by inch-dia)
| Step | Credit |
|---|---|
| Spools erected in position | 30% |
| Field joints welded (by inch-dia) | 40% |
| Supports installed | 10% |
| NDT complete and accepted | 5% |
| Hydrotest passed | 10% |
| Reinstatement | 5% |
Mechanical equipment
| Step | Credit |
|---|---|
| Set on foundation | 50% |
| Levelled and aligned | 20% |
| Grouted | 10% |
| Internals and dressing | 10% |
| Final alignment and box-up | 10% |
Electrical: cables
| Step | Credit |
|---|---|
| Cable pulled and dressed | 60% |
| Glanded and terminated (both ends) | 30% |
| Tested (insulation resistance, continuity) | 10% |
Instrumentation
| Step | Credit |
|---|---|
| Calibrated | 10% |
| Installed and supported | 35% |
| Hook-up (process and air) | 30% |
| Loop checked | 25% |
Engineering deliverables (drawings, documents)
| Step | Credit |
|---|---|
| Started | 10% |
| Internal check complete | 40% |
| Issued for review (IFR) | 60% |
| Client comments incorporated, issued for approval (IFA) | 80% |
| Issued for construction (IFC) | 100% |
Worked example
A piping test pack has 600 inch-dia of field welds and a budget of 1,500 man-hours. Spools are all erected, 300 of 600 inch-dia are welded, and half the supports are in.
Progress = 30% (spools) + 40% × 300/600 (welds) + 10% × 0.5 (supports) = 30 + 20 + 5 = 55%, so the test pack has earned 0.55 × 1,500 = 825 man-hours.
Tips
- Weight the steps by the effort they take, not by how visible they are. Erecting a spool looks like progress but is often less than half the work.
- Keep the final step meaningful (test, punch list, IFC) so items cannot sit at 95% for months.
- Do not change rules mid-project without re-baselining; the S-curve will jump.
Applying rules of credit in Planline
Either split the work into one activity per step with the step's share of man-hours, which gives the clearest Gantt chart, or keep one activity and record the credited quantity in the Progress entry sheet (in the example above, 55% of the scope quantity). Planline then calculates earned man-hours and the weighted overall progress.
Frequently asked questions
Who sets the rules of credit?
Normally the contractor proposes them in the progress measurement procedure and the client approves them before construction starts. Owners often have standard rules they require.
Should engineering progress use rules of credit?
Yes. Weighted steps tied to document issues (IFR, IFA, IFC) are the standard way to measure engineering progress objectively.
What is the difference between rules of credit and weightage?
Weightage sets how much each activity counts in the overall progress. Rules of credit set how much progress an activity earns for each step within it.
Related guides
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