The paper outlines a new model for demographic projections by detailed population categories that are required in the development of sustainable (elderly) health care systems and pension systems. The methodology consists of a macro-model (MAC) that models demographic changes at the population level and a micro-model (MIC) that models demographic events at the individual level. Both models are multistate models that rely on rates of transition between states of existence or stages of life. MAC focuses on transitions among functional states by age and sex. The transitions determine the distribution of cohort members among functional states. The output of MAC consists of cohort biographies. MIC addresses demographic events and other life transitions
at the individual level. It is a micro-simulation model that produces individual biographies. This paper describes approaches to functional population projection and provides a detailed description of the multistate model. It also contains an overview of the MicMac project.