Abstract
One of the future researches in manpower planning is to integrate the studies on both the quantitative and the qualitative aspects. This paper presents the relationships between the length of service at each calss and promotion policies such as promotion by seniority, promotion at random, promotion by ability, and promotion by the combination of seniority(α)and ability(1-α), respectively. Data on the length of service can be used in studies on the quantitative aspects. Namely, the use of data on the length of service under a particular promotion policy is a way to integrate the studies in the quantitative and the quanlitative aspects in manpower planning.
