Management must not only study the rate of demand, but the nature of demand as
well. Independent demand which comes from customer orders receives much more
attention than dependent demand which arises when higher-level assemblies are
required. In this case components are used only when actual assembly takes place,
generally at intervals, as opposed to the continuous rate of depletion of independent
demand. Examination of the movement of stock items indicates that the pattern of
independent demand varies from being almost constant to highly irregular. This has
implications for control, as has been discussed elsewhere[3].