Required operators
Manual work content divided by takt. What the flow needs, not what is rostered. The range beside it is the same figure in whole people: the theoretical minimum if work can be shared across processes, and the count if every process keeps its own operator.
Formula
In practice
The requirement is built from manual work content, not from a station's cycle time. Unattended machine time is excluded, and so is work hidden inside it — which is precisely why this cannot be computed from the cycle figure alone. Each process contributes its manual content multiplied by the passes it actually has to run, which include routing share, yield loss and rework, divided by its own available time.
The total comes out as operator-equivalents, and the design layer reports a range rather than a single answer: ceil of the total is the theoretical minimum if work can be shared across processes, while the sum of each process rounded up is the dedicated-coverage case. Neither is offered as proof that labour can be removed. Skill, distance, safety and simultaneous-attendance constraints decide that, and they require a Yamazumi study and verification on the floor.
How this is calculated
process operator load = manual work content × required process passes / process available time
required operators = Σ process operator loads
balance efficiency = required operator equivalents / assigned operators (uncapped)
Balance efficiency is uncapped, and above 1 means short-staffed. It was clamped into [0, 1], so an office needing 5.3 operator-equivalents from four people reported a comfortable 100% while the staffing plan beside it said two short. Same reasoning as capacity utilisation: the bar in the interface may stop at full, the figure may not. Note also that this is a staffing ratio and not the classical line-balance formula (work content over stations × bottleneck cycle); both are called balance efficiency in the field.
Manual content excludes unattended machine time and work hidden inside it —
which is why this cannot be computed from a station's cycle time alone.
Required passes include routing share, yield loss and rework. The design layer
reports a range: ceil(total operator equivalents) is the theoretical minimum
if work can be shared, while Σ ceil(process operator load) is the dedicated
coverage case. Neither is presented as proof that labour can be removed; skill,
distance, safety and simultaneous-attendance constraints require a Yamazumi
study and floor verification.
Common questions
Why does it report a fraction of an operator?
Because the load is a fraction. Rounding at each process and rounding once at the end give different answers, and both are published: the difference between them is exactly the work-sharing question, which is a floor decision rather than an arithmetic one.
Is the gap between this and my headcount a saving?
Not as reported, and deliberately so. The engine will not claim labour savings until work sharing has been demonstrated — the figure is an operational input to that conversation, not its conclusion.
Related terms
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Balance efficiency
The work the stream needs, in operator-equivalents, over the operators actually assigned to it. Deliberately uncapped:…
This definition is the one the product itself shows, read from its interface catalogue at build time.