Beta-distributed age in manpower planning models

Abstract

Many manpower planning models assume age to be normally distributed. In this paper we have examined the suitability of beta distribution for age. Beta distribution has a few properties, such as finite positive intercepts in the x-axis and adjustable skewness, that make it highly desirable as a distribution for age in a manpower planning model. In this paper we have developed an approach for dynamically computing the retirement probability, and hence the retirement rate, when the age of manpower in a pool follows beta-distribution. We have made a comparative evaluation of the two distributions in the framework of a simple manpower planning system dynamics model, and we have shown that various manpower-related variables assume more reasonable values for the beta-distributed age compared to the normal-distributed age. Thereafter we have applied the approach to a two-stage hierarchical manpower planning model in an R & D laboratory and have studied the behavior of the manpower-related variables under two recruitment policies. We have demonstrated in this paper that assuming beta-distributed age presents no difficulty while modelling for time-scale promotion, a combination of time-scale and merit promotion, and recruitment of persons at different age groups.