Government policies on disability - and criticism of them - rest in part on an understanding of the circumstances of disabled people informed by cross-sectional survey data, dividing the population into 'the disabled' and 'the non-disabled'. While conceptual debates about the nature of disability and associated measurement problems have received some attention, the dynamic aspect of disability has been largely overlooked. This paper uses two approaches to longitudinal data from the British Household Panel Survey to investigate the complexity behind the snapshot given by cross-sectional data. First, a detailed breakdown is given of the working-age population who are disabled at any one time by the 'disability trajectories' they follow over a seven-year period. Second, the expected duration of disability for those who become disabled during working life is examined. The results show that only a small proportion of working age people who experience disability are long-term disabled, despite the fact that at any one time, long-term disabled people make up a high proportion of all disabled people. Over half of those who become limited in activities of daily living as adults have spells lasting less than two years, but few who remain disabled after four years recover. Intermittent patterns of disability, particularly due to mental illness, are common. The assumption, contrary to evidence presented in this paper, that 'once disabled, always disabled' has lead to disability benefits being seen as a one-way street, an outcome which marginalises disabled people and is costly for the benefit system. In addition, eligibility criteria for disability benefits and employment support for disabled people often do not reflect the non-continuous nature of some disability. Policies which fail to distinguish between the different trajectories which disabled people follow are unlikely to be successful
