SUMMARYA methodology is presented to deal with heterogeneity due to observable variables in modeling personnel systems. For a manpower system, a model based on personnel profiles is introduced. The proposed algorithm concerns an analysis of the evolution of personnel profiles under time-discrete Markov assumptions. In this way, based on an historical personnel database, the estimation of transition probabilities of profiles as well as the computation of forecasts on the evolution of the manpower system can be found. Based on the presented procedure, a policy supporting software package has been developed for the Belgian Federal Government (research project financed by Federaal Wetenschapsbeleid).