Measuring functioning and disability using household surveys: metric properties of the brief version of the WHO and World Bank model disability survey

Abstract

Background The Model Disability Survey (MDS) is the current standard recommended by WHO to collect functioning and disability data. Answering calls from countries requesting a version to be implemented as a module that could be integrated into existing surveys and be used for monitoring disability trends and for data disaggregation, WHO developed the brief MDS. The objectives of this paper are to evaluate the metric properties of the disability metrics generated with the Brief MDS and the precision of the Brief MDS in comparison with the full MDS. Results The partial credit model, a unidimensional model for polytomous data from the Rasch family, was applied to evaluate psychometric properties using data from national MDS implementations in Chile (N = 12,265) and in Sri Lanka (N = 3000). The Brief MDS generates valid metrics for measuring disability, from the perspectives of capacity and performance, thereby achieving good levels of measurement precision in comparison with its full counterpart. Conclusion Given the scarcity of valid functioning and disability modules for household surveys, the Brief MDS represents a milestone in disability measurement. The Brief MDS is currently used by countries to monitor disability trends over time, which is especially important to evaluate the impact of health policies and public health interventions, to disaggregate indicators of the Sustainable Development Goals, and to monitor the implementation of the UN Convention on the Rights of Persons with Disabilities (CRPD).

Demographic and environmental factors associated with disability in India, Laos, and Tajikistan: a population-based cross-sectional study

“…The MDS has been piloted, validated, and implemented on a national and regional scale in countries around the world, including Afghanistan, Cameroon, Chile, Costa Rica, Pakistan, the Philippines, and Sri Lanka [ 12 ]. For this study, the core modules of the MDS were condensed into a brief version (Brief MDS or B-MDS), which can be administered as a short ten- to fifteen-minute disability module as a part of other population surveys [ 13 ].…”

WHO Functioning and Disability Disaggregation (FDD11) tool: a reliable approach for disaggregating data by disability

“…More specifically, the 11 questions constituted a separate module on intrinsic capacity that was part of the brief version of the MDS. Details on the development of the brief MDS are reported elsewhere [11], but a short summary is provided below. WHO developed the full version of the MDS in 2014 to answer the global call for collection of comparable and valid disability data.…”

“…WHO developed the full version of the MDS in 2014 to answer the global call for collection of comparable and valid disability data. The MDS represented an evolution in the concept of disability measurement assessing three aspects to fully describe the experience of disability -1) capacity, defined as the synthesis of all intrinsic physical and mental capacities of a person, determined by their health condition or impairments; 2) functioning, defined as the outcome of the interaction between the individual's capacity and features of the environment; and 3) environmental factors that affect the individual's lived experience of disability [11].…”

How to capture the individual and societal impacts of syndemics: the lived experience of COVID-19

“…At the population level, a comprehensive ICF-based survey like the WHO and the World Bank MDS is suitable for generating an overall score of functioning with metrical properties, an indicator that can complement mortality and morbidity indicators by proving a measure of how COVID-19 impacts the functioning and health of individuals. Moreover, the MDS can support the identification of key social and economic determinants of the functioning of persons with or without COVID-19 29 and the impact on the spread of the disease itself across the population. The MDS—the current standard recommended by WHO to assess functioning at population level—is a dedicated survey available online in two formats: a stand-alone comprehensive survey, including a large inventory of environmental factors, and a brief functioning module (brief MDS) for inclusion in household surveys.…”

“…The MDS—the current standard recommended by WHO to assess functioning at population level—is a dedicated survey available online in two formats: a stand-alone comprehensive survey, including a large inventory of environmental factors, and a brief functioning module (brief MDS) for inclusion in household surveys. 28 Since the brief MDS is concise and generates good overall scores of functioning, 29 it might be a good choice for assessing functioning in the context of COVID-19 in the scope of routine household surveys.…”