TWI job instruction explained

What a job instruction breakdown is

Job instruction is a way to teach a worker a new job. It comes from Training Within Industry (TWI), a US government program that ran from 1940 to 1945. Before teaching, the trainer writes a breakdown of the job. The breakdown has three columns.

• Important steps. The points in the job where the work moves forward. Each one is a few words long, such as "Put the wheel on the hub studs."
• Key points. The details in a step that make or break the job, keep the worker safe, or make the work easier. Here each key point is marked safety, quality or technique, so the worker knows why it is there.
• Reasons. Why each key point matters. A worker who knows the reason is more likely to keep doing the key point.

The trainer then teaches from the sheet in four steps: prepare the worker, present the operation, try out performance, and follow up.

Why write a breakdown

Without a breakdown, a new worker learns by watching whoever is next to them. Each person teaches the job a little differently, and their shortcuts get passed on too. Important details get left out because an experienced worker does them without thinking.

A breakdown makes the trainer decide what matters before they teach. Every new worker hears the same steps, the same key points and the same reasons. By the end of World War II, over 1.6 million workers in over 16,500 US plants had a TWI certificate.

A breakdown covers one job. Standardized work sets the order and timing for the whole operation. The breakdown is how you teach one job in it to a new person.

How to write a breakdown sheet

1. 1
   Do the job yourself

   Do it slowly, the way you want it taught. Notice each point where the work moves forward. Those are the important steps.
2. 2
   Write down the important steps

   Use a few words for each, starting with a verb. Most jobs have three to seven. If you have twenty, group them.
3. 3
   Find the key points

   Do the job again. At each step, ask three questions. What could make or break the job? What could hurt the worker? What makes the work easier? Each answer is a key point. Keep only the few that matter most.
4. 4
   Write a reason for each key point

   Say what goes wrong if the key point is skipped, such as "Too loose and the wheel can come off." A reason like "Nuts should be tight" does not tell the worker anything.
5. 5
   Test it on a new worker

   Teach the job from the sheet. If the worker gets a step wrong, check whether the sheet is missing a key point.

The free TWI job instruction tool lays out the three columns, adds a photo for each step and prints the sheet.

The four steps of job instruction

1. Prepare the worker. Put them at ease. Tell them which job they will learn. Find out what they already know about it. Stand them where they can see the work.
2. Present the operation. Do the job and say each important step, one at a time. Do it again and stress each key point. Do it a third time and give the reason for each key point. Teach no more than they can take in at once.
3. Try out performance. Have the worker do the job, and correct mistakes as they happen. Have them do it again and tell you each important step. Then again with the key points, and again with the reasons. Keep going until you know they know.
4. Follow up. Let them work on their own. Tell them who to ask for help. Check on them often at first, then less often.

TWI's rule for the trainer was "If the worker hasn't learned, the instructor hasn't taught." When a worker gets the job wrong, look at the sheet and the teaching first.

Fill in a breakdown yourself

Here is the wheel job again with the key points and reasons left blank. For each step, pick one key point and one reason. Some cards are common mistakes. They repeat the step, put a reason in the key point column, or tell the worker to do the thing that causes the problem. Check the sheet to see what each choice would lead to.

Common mistakes

• Writing the step again as a key point. "Tighten each lug nut" tells the worker nothing new. A key point says how to do the step well.
• Leaving out the reasons. Workers drop key points they do not understand, most often when the line is busy.
• Writing vague key points. "Be careful" and "as tight as you can" cannot be checked. Write the number, such as 120 Nm.
• Skipping the try-out. A worker who has only watched has not shown they can do the job. Have them do it and tell you the key points and reasons.