Disability as a health outcome deserves more attention than it has so far received. With people living longer and the epidemiological transition from infectious to noncommunicable diseases as the major cause of health burden, we need to focus attention on disability - the non-fatal impact of heath conditions - over and above our concern for causes of mortality.With the first Global Burden of Disease study, WHO provided a metric that enabled the comparison of the impact of diseases, drawing on a model of disability that focused on decrements of health. This model has since been elaborated in the International Classification of Functioning, Disability and Health as being either a feature of the individual or arising out of the interaction between the individual's health condition and contextual factors. The basis of WHO's ongoing work is a set of principles: that disability is a universal human experience; that disability is not determined solely by the underlying health condition or predicated merely on the presence of specific health conditions; and finally, that disability lies on a continuum from no to complete disability. To determine whether interventions at individual or population levels are effective, an approach to disability measurement that allows for an appropriate and fair comparison across health conditions is needed. WHO has designed the Model Disability Survey (MDS) to collect information relevant to understand the lived experience of disability, including the person's capacity to perform tasks actions in daily life, their actual performance, the barriers and facilitators in the environment they experience, and their health conditions. As disability gains prominence within the development agenda in the United Nations Sustainable Development Goals, and the implementation of the United Nations Convention on the Rights of Persons with Disabilities, the MDS will provide the data to monitor the progress of countries on meeting their obligations.The lesson learned from WHO's activities is that disability is a universal human experience, in the sense that everyone can be placed on a continuum of functioning and either currently experiences or is vulnerable to experiencing disability over the course of their lives. This understanding of disability is the key to mainstreaming disability within the public discourse.