01 · Recognize
Operations & capacity
How do we improve output, service or cost?
You are in this case when
- Queues, delays, utilization or throughput appear in the prompt.
- The client wants more from the same assets before buying new ones.
02 · Structure
Which drivers matter?
- 01
Process
Map the stepsCycle times, handoffs, queues and the bottleneck.
- 02
Capacity & economics
Demand vs capacityUtilization, labor, yield, downtime and the cost of one more unit of capacity.
- 03
Improve & implement
Fix the constraintScheduling, maintenance, quality, outsourcing or investment, in that order of cost.
Utilization = actual output ÷ available capacity (same period, same units)
03 · Solve
Work the scratch sheet.
Illustrative practice scenarioA clinic has three exam rooms. A visit takes 20 minutes and the day is 8 hours. Demand is 60 visits a day. One intake desk checks in 6 patients an hour.
- Room capacity3 rooms × (480 ÷ 20) = 72 visits a day
- Room utilization60 ÷ 72 = 83.3%
- Intake capacity6 × 8 = 48 patients a day, below demand of 60
- Fix the constraintA second intake desk lifts intake to 96; rooms at 72 become the next limit
Patients queue at the desk, not the rooms. Adding a fourth room changes nothing; one more intake desk raises throughput to the room limit of 72.
Work backward from an answer
If the answer is “add capacity”, the bottleneck must be the thing you are adding. So find the constraint before pricing the expansion.
04 · Recommend
Make the call in three buckets.
Add a second intake desk, not a fourth room.
Intake handles 48 patients a day against demand of 60; rooms sit at 83% and are not the limit.
Measure wait time for two weeks after the change. Risk: the constraint moves to the rooms at 72 and the next ask is a room.
“I would locate the system constraint before adding capacity anywhere.”
Watch for: Speeding up a step that is not the bottleneck adds nothing. High utilization makes queues worse when demand varies.
Special sauce
Bring a real company into the room.
If demand shifts toward a newer node, can spare older-node capacity meet it? Ask which equipment and processes can transfer before recommending an expansion.
Read the story →operations · PaymentsVisaIf a merchant asks to cut payment costs, which fee can the network change and which belongs to another participant? Trace a transaction before proposing a price cut.
Read the story →Three terms to use
- Bottleneck
- The step with the least capacity; it sets system throughput.
- Utilization
- Output divided by capacity for one step over one period.
- Cycle time
- Time for one unit to pass through a step or the whole process.
Original Harper practice examples; every figure is illustrative. Adapt the questions to the client’s objective, timing and constraints.