Load Balancing Between Operators

Balancing workloads requires tasks and conditions to be measured

Workload balancing allocates work with attention to sequence, capacity, skills, safety, and variation. It does not mean keeping everyone occupied for the same share of a shift. Waiting for an automatic machine may be part of the defined method; necessary support work may not directly transform a product.

Sampling estimates activity-state proportions. Redesign also requires operation times, precedence relationships, and constraints. Different observed proportions do not establish differences in effort or automatically identify a bottleneck.

Design a valid comparison

Define the population and shifts to which the conclusion should apply. Distinguish assembly, setup, support, waiting, and breaks using observable rules. Do not infer fatigue or motivation from a posture or a single observation.

Schedule random times across the relevant period and record missed visits. People observed in one round may share a cause and have correlated states. Counting their records as independent observations can make intervals too narrow.

Teaching example: 65 out of 100 observations

Assume 100 independent, representative observations of one workstation, with 65 classified as direct work. The estimate is 65%, not a known true productivity of 65%. The approximate 95% Wilson interval is 55.3–73.6%; it describes sampling uncertainty under the model. NIST explains proportion intervals.

The other 35 records are not automatically removable time: they may include required support or breaks. The interval does not account for classification error, product changes, or missing coverage.

Test a reallocation

1. Investigate repeated waiting against material supply, sequence, and capacity.
2. Check which tasks can move and what training or resources they need.
3. Trial the change without reducing necessary rest or compromising quality.
4. Compare periods with compatible mix, scope, and definitions.
5. Evaluate good output, workload, and conditions, not occupancy alone.

There is no universal improvement percentage, nor an end-of-shift productivity loss that can be assigned without measurement.

Do not call a human-activity indicator OEE

OEE requires equipment availability, performance, and quality with defined time and output denominators. A direct-work proportion is not a substitute. The OEE calculation uses run time, ideal cycle time, total count, and good count.

Occupational risk assessment and employment obligations require their own procedures. Sampling can inform organizational review; it does not certify fairness, legal compliance, or the absence of risk.