What is a work instruction?
A work instruction is the lowest-level working document in a quality or operations system. Where a procedure describes a whole process, a work instruction describes how one person performs one task: fitting a seal, setting a machine, cleaning a mixer, inspecting a weld. It is written for the person with the tool in their hand, so it is short, specific and usually shows photos, drawings or a diagram.
The terms work instruction, job instruction, operator instruction and task instruction are often used for the same thing. In some businesses a work instruction is also called a standard work instruction (SWI) or a job breakdown. The name matters less than the test: could a trained person do the task correctly from this page, at the workstation, without asking anyone?
What is the purpose of a work instruction?
Work instructions exist to make a task repeatable. They do four jobs:
- Reduce variation. Two operators on different shifts follow the same sequence and settings, so the output does not depend on who is on.
- Protect quality and safety. The checks, limits and hazards sit at the exact step where they matter, not in a policy document.
- Speed up training. A new starter learns from the instruction and a trainer, then is signed off against it.
- Give the team a baseline. An improvement can only be proven against a written starting point, and the updated instruction then becomes the new baseline.
They also support audits. Standards such as ISO 9001 expect documented information where its absence would affect conformity, and a work instruction is a common way to meet that for a hands-on task.
What goes in a work instruction?
A good work instruction is brief but complete. Most include:
- Title and ID, version, owner and date, so the current revision is obvious.
- Purpose and scope: the task, the equipment and who it applies to.
- Tools, materials and PPE needed before step one.
- Numbered steps, each starting with an action verb, in the order the work is done.
- Key points and reasons: the detail that makes or breaks safety, quality or ease, with a short why.
- Photos, drawings or short video at the steps where words struggle.
- Quality checks and limits: what to measure, the acceptable range and what to do when it fails.
- Safety warnings placed at the step they apply to.
- Escalation: who to call or which action to raise when something is out of standard.
Work instruction vs SOP
An SOP covers a procedure and the work instruction covers one task within it. The SOP says what must be done, by whom and why; the work instruction says how, one step at a time. For the full picture of the higher-level document, see what an SOP is.
| Work instruction | SOP | |
|---|---|---|
| Scope | One task, one person | A procedure, often across roles |
| Detail | Step level, photos, settings, key points | Purpose, responsibilities, process overview |
| Where it lives | At the workstation or on the operator's device | In document control |
| Changes when | The task, tool or method changes | Policy, regulation or the process changes |
Standard work adds the time and sequence the team commits to. All three should agree with each other.
How do you write a work instruction?
- Choose the task. Start with safety-critical, error-prone or frequently trained tasks.
- Watch it done at the gemba. Observe an experienced operator several times and note the sequence, the key points and the hesitations.
- Break it into steps. One action per step, in the order done. Split any step that needs two verbs.
- Add key points and reasons. Record what makes the step safe, correct and easy, and why it matters.
- Show it. Take photos or draw the setup at the steps where a picture is quicker than a sentence.
- Test it with a newcomer. Ask someone who has not done the task to follow it while you watch. Every question they ask is a gap.
- Approve, train and publish at the point of use. The owner approves it, people are trained and signed off against this version, and the current revision is where the work happens.
- Review on change and on audit. Update it whenever the method changes or an audit finds it is not being followed.
Work instruction example: changing a sealer jaw
Purpose: replace the sealer jaw on a packaging line safely and to the correct setting. Scope: Line 2, maintenance and trained operators. Tools: lockout lock, torque wrench, jaw gauge. Steps: 1. Stop the line and apply lockout. 2. Wait for the jaw to cool to the safe-touch temperature shown on the display. 3. Remove the two retaining bolts and lift the jaw straight out. 4. Fit the new jaw and hand-tighten the bolts. 5. Tighten both bolts to the specified torque. 6. Check the jaw gap with the gauge. 7. Remove lockout, run five test packs and check seal integrity. 8. Record the result and the jaw serial number. Key point at step 5: tighten evenly, because an uneven jaw seals badly on one side. Each step has a photo, and the safe-touch temperature is shown on the page.
What are the common mistakes with work instructions?
- Too much text. A paragraph per step goes unread. Use short steps and pictures.
- Written at a desk. If the author has not watched the task, the document misses the real key points.
- Out of date. A wrong or old instruction is worse than none, because people trust it.
- Hard to find. A binder or shared folder away from the line means people work from memory.
- No link to training or audits. A signature on a form does not show the person can do the task, and nobody checks the instruction is used.
How do you keep work instructions current?
Treat them as living documents owned by the area, not files owned by an office. Review them when the method changes, after a defect or incident that points to the instruction, and when an operator suggests a better way. Check them at the work: layered process audits and gemba walks ask whether the instruction is posted, current and followed. Link them to the skills matrix so a changed instruction shows who needs re-training, and make the current version available on a phone, tablet or screen at the workstation instead of on paper. See digital work instructions for how that looks in practice.