Book excerpt: The paper presents an overview of definitions and concepts applied by the United Nations and further describes different concepts and methodologies that are available to quantify and measure disability. It presents findings of an empirical four country (Antigua and Barbuda, Saint Lucia, St. Vincent and the Grenadines, and Trinidad and Tobago) study using recent census data. The study also looks into the accessibility of assistive devices, living arrangements and social activities of those affected by these ailments.