In 1940, when the United States decided to enter World War II, the country faced a severe labor shortage for manufacturing and producing critical war equipment such as aircraft, warships, anti-aircraft guns, and military supplies. At that time, there were approximately 8 million unemployed people in the U.S., most of whom had never been involved in industrial production.

TWI played a pivotal role in helping the United States rapidly overcome this workforce constraint, enabling factories to efficiently produce equipment, weapons, and essential supplies to support the U.S. military and its Allies. TWI programs were also deployed in field hospitals. This contribution is widely recognized as a critical factor in the Allied victory in World War II.

After the war, the U.S. government expanded TWI programs internationally, deploying TWI experts to support Allied nations in Europe, as well as reconstruction efforts in Japan and Germany. These initiatives significantly contributed to the rapid recovery and rebuilding of war-torn economies.

How did TWI achieve such recognition and impact?

TWI focuses on equipping front-line supervisors – those directly responsible for daily operational performance on the shop floor or in service environments – with essential management and leadership capabilities. Its core objective is to enable supervisors to rapidly transfer knowledge and job skills, elevate workforce capability, and establish a strong foundation for safety, quality, and productivity. At the same time, TWI promotes continuous improvement and fosters a culture of respect, collaboration, and effective feedback within teams.

The TWI framework consists of four foundational training programs:

① Job Instruction (JI): Training Within Industry for effective job instruction

② Job Methods (JM): Improving work methods for productivity

③ Job Relations (JR): Strengthening leadership and people management

④ Job Safety (JS): Ensuring safe work practices

A classic example of TWI’s “knowledge replication” capability can be seen in its early application. Shortly after its establishment, TWI was tasked with developing skilled labor for precision prism grinding—an essential component of anti-aircraft targeting systems. At that time, the U.S. government required 350 skilled workers, yet very few qualified individuals were available. Traditionally, it took up to five years to train a technician to meet required standards.

TWI experts addressed this challenge by breaking the process down into 22 discrete tasks, most of which required minimal prior skill or experience. Using the Job Instruction (JI) method, they trained new workers step by step, starting with simpler tasks. Through structured training and continuous improvement of the training process itself, TWI successfully reduced the time required to develop a skilled prism grinder from five years to just two months.

At the heart of TWI lies the principle of the “Multiplier Effect”—systematically replicating knowledge and capability across the organization. TWI trainers strictly follow the standardized 4-Step Method, emphasizing discipline, completeness, and avoiding reliance on memory alone.

 

 

TWI’s mission is to train supervisors and managers to learn, practice, and apply these standardized methods (the “J programs”) effectively within real operational environments.

Remarkable Impact – TWI in the United States

From its establishment in 1940 to August 1945, TWI in the United States achieved significant scale and impact through certification programs. Given below is the tabulation of results collected by TWI at seven different intervals during its service.

Table: TWI Plant Results

The number of industry people to go through the five, two-hour sessions for each training program was quite large. Even though the number of those who attended the sessions does not necessarily directly translate to results, it does give an idea of the magnitude of coverage the TWI Service achieved during its short five-year existence. Considering that all of the programs had to be developed and that the Service actually started down the consulting path during its first year, the number of people trained is quite impressive.

When TWI operating service ended September 30, 1945, the following
certification totals appeared:
Job Instruction…………………..……………………….1,005,170
Job Methods……………………………………….………..244,773
Job Relations………………………………….…….………490,022
Union Job Relations………………………………………….8,856
Program Development……………………………………….1,829

Total………………………………………..………..….……1,750,650

 

Reference:

War Production Board, Bureau of Training, Training Within Industry Service, September 1945, The Training Within Industry Report: 1940-1945, (Washington D.C.: U.S.Government Printing Office), page 92.

Lean Frontiers, The History of TWI (Training Within Industry), February 21, 2021

Jim Huntzinger, The Roots of Lean, Target Magazine, Volume 18, Number 2, Second Quarter 2002