Why is TWI Job Instruction the 'missing link' in Lean?

TWI Job Instruction (TWI JI) is bridge that connects the written standard to what people actually do on the shop-floor or in the office. Those of us who spend a lot of time observing and improving the work of others notice quickly that the way people do their work frequently is not consistent and there are even more differences between one person and another.

This may be okay if the work performed is not critical to quality or there is capacity is much greater than demand. But given the fiercely competitive nature of manufacturing and most types of other repetitive work, consistency in the way work is performed is essential for long-term success.

For over 70 years TWI Job Instruction has played in central role in continuous improvement at Toyota, the automotive manufacturer renowned for its exemplary manufacturing system that has become to be known as Lean manufacturing. We have learned a lot from Toyota about manufacturing practices that shorten lead-times, drive world-class quality and boost productivity. Yet for many years the Lean manufacturing and Lean Service communities focused on the visible tools of Lean, but were not aware of, and did not understand the significance of, the underlying practices that underpinned the Lean tools , amongst them TWI Job Instruction.

TWI Job Instruction connects ‘say what we do’ with ‘do what we say'.

In the meantime, whilst there was talk about the importance of standardisation, Lean Manufacturing and Lean Service practitioners used visual tools, such as lines to mark out standard locations for materials and equipment and mistake proofing devices to reduce mistakes that affect quality. These practices would help but fall short of achieving process stability that TWI JI helped create at Toyota. Efforts to standardise job methods at a more detailed level would typically emphasise written documents, such as standard operating procedures and standard work instructions that engineers, managers and quality systems administrators spent a lot of time on, but workers frequently ignored. Therefore, despite rapidly growing and increasingly complex management systems, work resisted standardisation and true stability was rarely achieved.

TWI Job Instruction was the ‘missing link’ in Lean. It solves the problem of knowing that standardisation is important but not having a method to make it happen. It connects ‘say what we do’ with ‘do what we say’, consistently, every time. TWI JI codifies the ‘best way known today of performing a task’ and through a rigorous on the job training system, ensures that this standard sticks and delivers time and again good quality, at the lowest pace and cost.

By doing this, TWI Job Instruction creates the basis of stability that enables continuous improvement. Without rigorous standardisation through TWI JI, your new, better way of performing the work your Kaizen team has developed will remain just one of many, many ways of doing the work. TWI Job Instruction helps to lock the new standard in where it matters, not on paper but in the thinking and habits of our front-line workers.