1920s: Taylor's theories of management science, empowered by Carl Barth's machining slide rule technology, birth the concept of business process management (BPM).

1929: The Taylor Society in the USA releases a revised and updated practitioner's manual of scientific management: Scientific Management in American industry.

1932: Elton Mayo becomes the first to question the behavioural assumptions of scientific management. His studies conclude that human factors are often more important than physical conditions in motivating employees to greater productivity.