The implications of the individual quality of life (QoL) model of Schalock and Verdugo have made it the most cited QoL model in the field of disability. The QoL model is understood as a conceptual and applied framework for action that allows the materialization of the rights of persons with disabilities through the multidimensional assessment of these persons using QoL indicators, and the development of actions guided by these values and supported by evidence. The purpose of this work is to present the foundations of this model and offer a step-by-step guide to developing standardized QoL assessment instruments and providing evidence that supports their use to implement the model in practice. This paper explores relevant topics such as: (a) the need to identify critical population groups and contexts; (b) the identification of QoL indicators for said groups and contexts; (c) the development of items focused on the assessment of personal outcomes; (d) provision to the items of validity evidence based on content and pilot measure design and (e) validation process to gather evidence that supports the uses of the instrument. Last, a framework that allows using the evidence on personal outcomes as disaggregated and aggregated data at different levels of the social system is presented, thus highlighting the role of the model as a change agent regarding individuals, organizations and schools, and public policy.