How labour productivity is calculated
Labour productivity is typically expressed as the number of hours worked per unit of installed quantity. The formula is straightforward:
Example: 80 crew-hours ÷ 400 m³ excavated = 0.20 hours per m³
Lower hours per unit means higher productivity. When the actual rate exceeds the budgeted rate, the activity is consuming more labour cost per unit of production than planned.
Why labour productivity changes during a project
Productivity is not constant. It varies day to day and activity to activity based on operational conditions:
- Weather conditions — rain, heat, and cold reduce output and increase break time
- Equipment availability — crews waiting for machines lose productive hours
- Site logistics — access constraints, material staging, and travel distances affect output
- Material supply — late or incorrect deliveries stop work mid-shift
- Crew experience — new or unfamiliar crews may produce below planned rates until they build momentum
- Rework — correcting defective work consumes hours without adding new production
The cost impact of labour productivity drops
A 20% drop in labour productivity does not just mean the work takes longer — it means 20% more labour cost per unit of production. On a large activity, this translates to thousands of dollars in additional cost per week. When the drop goes undetected for several weeks, the accumulated overrun can consume the project contingency.
Detecting labour productivity drift with daily data
TCC captures each crew member's hours and the production quantities achieved per activity each day. By comparing actual hours per unit against the budgeted rate, TCC identifies productivity drift within 24–72 hours — while the activity is still in progress and corrective action is possible.
Project managers can investigate whether the cause is weather, equipment, material supply, or crew composition and make adjustments before the variance compounds.
Labour productivity and project estimating
Accurate labour productivity data from completed projects improves future estimates. When estimators can reference actual hours-per-unit rates from similar activities, bids become more competitive and contingency budgets more realistic.
For project control and estimating guidance, see Projestim AI — Construction Project Control Assistant