This paper is one in a series that introduces concepts of Just-in-Time-Personnel. Management of worker job time and assignment is in many ways analogous to inventory management. Idle workers represent unutilized, ''inventoried'' personnel, imposing potentially large costs on management. But a lack of workers when needed may force the use of otherwise unnecessary overtime or other emergency procedures, creating excessive costs analogous to costs of stockout in traditional inventory systems. A system having Just-in-Time-Personnel attempts to meet all demands for personnel at minimum cost by sharply reducing both excess worker inventory with its concomitant ''paid lost time'' and underage of worker inventory with its associated costs of stockout. In this paper, a workforce is assumed to comprise three types of equally proficient worker: full timers, scheduled part times and call up temporaries. Each day the facility employing the workers must perform an amount of work that varies randomly from day to day, according to a normal distribution. If, due to random absenteeism, insufficient numbers of scheduled workers appear on a given day, management must employ overtime and/or temporaries to complete the workforce complement. For large facilities, we formulate this problem mathematically and develop an algorithm for management to optimally configure the workforce, where the design criterion is minimization of average daily cost, and where certain reasonable management-stated constraints limit the number of design options available.
