where k ð0 # kÞ denotes the degree of
controllability a manager can exercise. If k ¼ 0;
y ¼ 1 and the manager does not have the ability to
control the inventory level with his process
improvement effort. On the other hand, if k $ 1;
the manager has maximum control over the
inventory level. For a given k, by increasing a2, he
can effectively reduce the inventory levels. In order