Cost driver
A cost driver is a structural factor which determines the cost of an activity or a change in its cost. The Chartered Institute of Management Accountants defines a cost driver as:[A] cost driver is any factor which causes a change in the cost of an activity, although a different meaning is assigned to the term by the business writer Michael Porter, who states:"cost drivers are the structural determinants of the cost of an activity, reflecting any linkages or interrelationships that affect it".