The dynamic household as a logical concept and its use in demography

Event history models for aggregate units such as households are complicated by the fact that such entities do not have a well-defined identity through time. The difficulties of applying conventional transition-based models to household change are discussed. More generally, what constitutes 'time' and 'change' are also considered. It is argued that many changes occurring within households such as leaving home are better-considered as 'fuzzy' than crisp phenomena. An alternative perspective based on household change considered as an evolving network is proposed The implications for sample designs which are designed to track explicit household dynamics (such as the Panel Study on Income Dynamics) are discussed. The ways in which particular forms of analysis come to dominate the scientific literature, including those for analysing household change is discussed in relation to non-linear dynamic models. Finally, it is argued that there would be considerable benefits if insights available from the physical, mathematical and biological sciences were to be more widely incorporated within technical demography.