Division of labour, the separation of a work process into a number of tasks, with each task performed by a separate person or group of persons. It is most often applied to systems of mass production and is one of the basic organizing principles of the assembly line. Breaking down work into simple repetitive tasks eliminates unnecessary motion and limits the handling of different tools and parts. The consequent reduction in production time and the ability to replace craftsmen with lower-paid unskilled workers result in lower production costs and a less expensive final product. Contrary to popular belief, however, division of labour does not necessarily lead to a decrease in skills—known as proletarianization—among the working population. The Scottish economist Adam Smith saw this splitting of tasks as a key to economic progress by providing a cheaper and more efficient means of producing goods.