Which management theory was based on understanding each part of a task, selecting the right workers, providing adequate training, and scientifically planning the work to maximize output?

Taylorism

Explanation:

Taylorism, often referred to as Scientific Management, was the first theory of management to focus specifically on analyzing and optimizing workflows. These theories of process optimization helped drive the Fordist shift to mass production which occurred in the early part of the 20th Century.  Taylorism can be boiled down to 4 principal points:  The method of doing a task should be informed by a scientific investigation of the task  , employees should be selected and carefully trained for tasks  ,tasks should have detailed instructions and should be subject to supervision  and management should evaluate tasks and formulate optimized approaches for the workers to follow .

Some forms of analysis might be done by timing how long it takes a worker to do a task, others by weighing raw materials. Process analysis, for Taylor, had to look at both the minutiae of the process composition and the detail of the physical acts required to complete the process. The elements of process improvement Taylor advocated for were successful in regards to processing materials; changing the way steel was cut and patenting that process. Yet, during his life, Taylor struggled to achieve quite the same success improving the efficiency of workers.  Taylorism was first scientifically understanding how the production process worked and then supporting the managers of a workplace to intimately train workers to work at maximum efficiency. This way, the means towards higher returns is paved with a well-managed, harmonious relationship between managers and workers. In theory, this would have been a much more sustainable model for an organization. But despite that promise, people, although genetically similar, are intrinsically unique and complex. Aligning different minds and ushering people to a new way of working (from individual craft, to standardized production), sometimes require more time and effort than bringing in a new piece of technology.

3rd the reason why is because of management and leadership