Grow Without Breaking

Small batches and the five whys

You batch everything to be efficient — all the invoices at month-end, all the deliveries on Friday — then discover a mistake you already made 200 times. Small batches hurt less because they fail sooner.

The principle

Small batches surface defects while they're still small. The counter-intuitive proof: stuffing envelopes one-at-a-time (fold, insert, seal, stamp, repeat) usually finishes SOONER than doing all the folding, then all the inserting — because if the envelopes turn out too small, the batch method reveals it only after every letter is folded. Single-piece flow catches the error on letter one.

How the books connect

A big batch feels productive — lots of motion, everything moving together — but it hides errors until the very end and then multiplies them across the whole pile. A small batch feels slower yet finishes faster and safer, because rework is caught at piece one instead of piece two hundred.

The principle

When something does break, don't fix the symptom — dig to the root by asking 'why?' about five times. The surface cause is always technical ('the machine jammed'); five whys down you reach a process or training gap ('no one was ever taught to service it'). Fix that, sized to how often the problem bites.

Ask why five times, then fix the process
  1. State the symptom in one plain sentence — what the customer actually experienced.
  2. Ask 'why did that happen?' and answer with a fact, not a guess.
  3. Ask 'why?' of that answer, and again — about five times, until you hit a process or training gap.
  4. Fix the process at the root, sized to how often the problem bites — small problem, small fix.
  5. Say it out loud: five whys, not five blames — if your answer is a person's name, ask why the system let it happen.
Five whys, one real failure

Symptom: a customer got the wrong order. Why? The ticket was misread. Why? It was handwritten and rushed. Why? Two orders arrived at once with no way to separate them. Why? There's no numbered-ticket process. Why? No one was ever trained to set one up. Root: a missing process, not a careless person. Fix: numbered tickets — proportional to how often it bites.

Machine jammedSymptomwhy?A part wore outwhy?It wasn't lubricatedwhy?No maintenance schedulewhy?No one was trainedwhy?No onboarding processRootFive whys, not five blames
A ladder descending from a surface technical symptom through five 'why?' rungs to a human/process root — with a 'five whys, not five blames' banner and fix-sizes that grow with how often the problem strikes.
Try it
📌 Do this Monday

Take the last thing that went wrong this week and ask 'why?' five times on paper until you reach a process or training gap. Write one small fix at that root — and make sure it names no person to blame.

Takeaway

Work in small batches so mistakes surface cheap, and when one does, ask why five times to a process root and fix the system in proportion to the pain — the process, never the person.

Grow Without Breaking