Capacity and Staffing

How Many People Do I Need on This Line?

Staffing gets answered by feel more than any other question on the floor. Too few people and the line misses; too many and the hours show up in the budget review. The math is short once you have takt and work content.

What Is Usually Going On

  • Headcount is carried over from history, not built from work content and demand.
  • Work content is unknown or out of date.
  • Balance loss, absence and training time are not in the number.
  • T1 work content is used as if it were what the floor delivers.

How to Fix It

  1. Set taktTakt = net available time per shift / units needed per shift.
  2. Get work contentSum touch time per unit across all stations. That is T1: the hours the job needs with no losses.
  3. Get expected hoursRecent actual hours per unit with a challenge applied. That is what the floor will take now.
  4. Compute the minimumOperators = work content per unit / takt, rounded up. Do it for T1 and for expected hours: staff to expected, improve toward T1.
  5. Add what the math leaves outBalance loss, absence, training and support roles. Show each as FTE so it can be challenged.
  6. Check the stationsLay the work out per station on a yamazumi. If a station is over takt, the count is not the problem, the balance is.
Make shop (asset-bound)
People are rarely the limit; machine hours are. Size the machines first, then heads per machine or cell from load, unload and setup. One person may run several machines.
Assembly shop (labor-bound)
The work is labor-bound. Heads come from work content divided by takt plus balance loss. An added person adds output only if the work can be split.

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When It Moves to the Floor

The same work as an offline file you keep: saved scenarios, print and export, no internet needed on the floor.

Common Questions

What is the difference between T1 and expected hours?

T1 is work content: hours per unit with no losses. Expected hours start from recent actuals with a challenge applied. Staff to expected so the plan is real, and use the gap to T1 as the improvement target.

Should I staff to the average day?

Staff to the planned rate, then cover absence with cross-trained people rather than an extra head on every station.

How do I account for absence?

Use your own absence rate over the last few months and add it as FTE, separate from work content, so it can be seen and managed.

Why did adding a person not raise output?

Output is set by the constraint. A person added anywhere else adds hours, not units.