Make the two crew records comparable
Prerequisites, sequence and stop points
- Define the same completed scope and accepted output unit. (not complete)
- Record actual hours by person and calculate worker-hours consistently. (not complete)
- Use the same loaded labour rate definition, revenue, tax and overhead basis. (not complete)
- Reconcile non-labour costs, rework, quality, equipment and site conditions. (not complete)
- Keep elapsed duration separate from worker-hours and commercial contribution. (not complete)
- Stop when a material difference cannot be normalised; gather another comparable observation. (not complete)
Compare five measures, not crew size alone
worker-hours = people × hours per person; accepted output per worker-hour = accepted output ÷ worker-hours; labour cost per accepted unit = loaded labour cost ÷ accepted output; job contribution = revenue − declared included costs; contribution margin = job contribution ÷ revenue
- people
- Crew members in the observed record (people) — user record
- hours per person
- Actual hours for the matched scope (hours/person) — user record
- accepted output
- Output meeting the same quality threshold (accepted units) — user record
- declared included costs
- Loaded labour and other matched job costs (CU) — business record or labelled assumption
Positive accepted output and revenue are required for per-unit and margin ratios. Faster completion is not automatically additional profit.
| Measure | Crew A | Crew B | Decision boundary |
|---|---|---|---|
| Crew and time | 3 people × 8 hours = 24 worker-hours | 4 people × 6 hours = 24 worker-hours | Headcount and elapsed time answer different questions |
| Accepted output | 100 units | 100 units | Same quality threshold required |
| Accepted output per worker-hour | 100 ÷ 24 = 4.17 accepted units per worker-hour | 100 ÷ 24 = 4.17 accepted units per worker-hour | Positive accepted output and matched work scope required |
| Loaded labour | 960 CU; 9.60 CU/unit | 1,080 CU; 10.80 CU/unit | No wage or productivity benchmark |
| Other job costs | 6,500 CU | 6,500 CU | Same declared scope |
| Total included job cost | 960 + 6,500 = 7,460 CU | 1,080 + 6,500 = 7,580 CU | Same declared inclusions and tax basis required |
| Contribution | 2,540 CU | 2,420 CU | Observed difference only; no causal winner |
| Contribution margin | 2,540 ÷ 10,000 = 25.4% | 2,420 ÷ 10,000 = 24.2% | Positive matched revenue required; not a target margin |
| Rework and acceptance | 100 accepted units; no separate rejected-unit or rework difference is recorded in this fictional case | 100 accepted units; no separate rejected-unit or rework difference is recorded in this fictional case | Same inspection threshold; no ranking if later rework records differ |
| Supervision and coordination | No separate supervision or hand-off amount is recorded for the 3-person crew | No separate supervision or hand-off amount is recorded for the 4-person crew | Unresolved trade-off; do not infer a coordination winner from headcount |
| Equipment and site constraints | Same fictional site window and declared equipment boundary | Same fictional site window and declared equipment boundary | STOP and rematch the records if access, equipment or interruptions differ materially |
| Service timing and downstream capacity | 8-hour elapsed completion; no downstream-capacity value is recorded | 6-hour elapsed completion; no downstream-capacity value is recorded | Two hours earlier is an observed timing difference, not automatically additional contribution |
Interpret Crew A versus Crew B
Labelled scenario
Both crews deliver 100 accepted units on a 10,000 CU tax-neutral job. Currency is rounded to two decimals and percentages, if used, to one decimal.
| Case or record | Inputs and arithmetic | Interpretation |
|---|---|---|
| Observed contribution | Crew A 2,540 CU; Crew B 2,420 CU; difference 120 CU | Crew A has stronger observed contribution in this narrow scenario |
| Elapsed completion | Crew A 8 hours; Crew B 6 hours | Crew B finishes two hours earlier, but released-capacity value is not assumed |
| Non-comparable case | Output, quality, equipment, skills or scope differs materially | STOP, normalise the record or treat the cases as contextual |
Trade-offs the margin number cannot settle
Use the calculation owner for the next step
- Job Costing & Margin Planner
Compare quoted and actual job economics and identify overruns
Questions and limitations
- Is the fastest crew the most profitable?
- Not necessarily. Compare worker-hours, loaded cost, accepted output and job contribution, then keep schedule value separate unless evidenced.
- How many jobs prove one crew is better?
- No universal count is supplied, and one job is not causal proof. Repeat comparable observations.
Sources and scope
- What is labour productivity? — U.S. Bureau of Labor Statistics: Measurement definition only; no US benchmark is imported.
- How labour input is measured — U.S. Bureau of Labor Statistics: Supports worker-hours and the skill-difference warning.
- Crew work-practice exploratory study — University of Technology Sydney: Narrow residential-rebar context; cited only for coordination confounding.