TWI (Training Within the Industry) is as old as Lean and developed in the USA during World War II.Rosie the riveter

There was a great lack of manpower to feed the war industry and for the first time women were employed in the industry. The challenge was to train these new workers  as quickly and efficiently as possible. TWI was developed for this, the method was transferred to Japan after the war and is virtually unchanged ever since. The method is ideal for defining standard work and offers a standard way of training, making the training short, efficient and independent of the trainer.

There is a great similarity with the 4-step model (see 'On the Job Training'), but there are also differences:

The TWI method is based on two principles:

• Capture the sequence of actions, key points of those actions and reasons for those key points on one piece of paper.
                The WHAT, HOW and WHY.
• Train the WHAT, HOW and WHY effectively and efficient to a trainee.

This is done in 4 steps:

Step 1: Prepare

• Put the trainee at ease.
• State the job.
• Find out what the trainee already knows.
• Get him interested in learning job.
• Place in correct position.

Step 2: Show

• Tell, show, and illustrate one IMPORTANT STEP at a time.
• Repeat, and stress each KEY POINT.
• Repeat, and explain the REASON for each key point.
• Instruct clearly, completely, and patiently, but no more than he can master.

Step 3: Do

• Have the trainee do the job, correct errors.
• Have the trainee do the job and explain each IMPORTANT STEP.
• Have the trainee do the job and explain each KEY POINT.
• Have the trainee do the job and explain the REASON for each key point.
• Make sure the trainee understands.
• Continue until YOU know the trainee knows it.

Step 4: Follow Up

• Put the trainee on his own.
• Designate to whom to go to for help.
• Check frequently.
• Encourage questions.
• Taper off extra coaching and close follow up.