IFS Working Papers, Institute for Fiscal Studies (IFS) 01/15
The life-cycle framework is the standard way that economists think about the intertemporal allocation of time, e¤ort and money. The framework has a venerable history in the economics profession with roots in the in…nite horizon models of Ramsey (1926) and Friedman (1957) and the …nite horizon models of Fisher (1930) and Modigliani and Brumberg (1956). Developments since the 1950’s have considerably increased the breadth, depth and coherence of the framework so that the modern version provides a guide to thinking about the modeling of many life-cycle choices (such as consumption, saving, education, human capital, marriage, fertility and labor supply) while taking account of uncertainty in a rigorous way. However, the life-cycle framework is held in increasing disrepute within the profession. We believe that reports of the demise - or even ill health - of the theory are much exaggerated. In this article we provide a defence of the life-cycle framework as a source of models that can be taken to the data. We emphasize this distinction between the life-cycle framework (or tradition) and particular models with empirical content. The life-cycle framework is a conceptual framework within which we can develop useful models; in this view, there is no such thing as the life-cycle model, only particular life-cycle models.