We now turn to the specific constituents of a DLS, the universal material satisfiers of basic human wellbeing (summarized in Table 1). We group them into satisfiers of physical and social wellbeing dimensions respectively. We then indicate the material requirements more specifically, delineated into those that are a property of a household and those that represent aggregate societal requirements, which would be shared at some level of social organization. We then follow with an explanation (rationale) of each item. We specify indicators and minimum quantities including any empirical support, where relevant and feasible. We also indicate where context-specific customizations (such as through participatory processes) would be appropriate. Some of the constituents and their quantitative thresholds have been introduced and justified in earlier work (Rao and Baer 2012). We make reference to the U.N's Sustainable Development Goals (SDG) where relevant.
Universal satisfiers Adequate nutrition, including macronutrients (energy, protein) and micronutrients (including iron, zinc and vitamins); cold storage.
Household requirements Minimum daily (context-dependent) intake of total calories, protein, vitamins and minerals; a modest sized refrigerator (e.g., 100 l).
Rationale Nutritional requirements are a complex but well-trodden field of public health. It is well known that in many developing countries malnourishment (among the poor) and obesity (among the middle and higher income) are prevalent and growing (FAO 2008). This has contributed to health disparities in these countries (Hawkesworth et al. 2010). More recent evidence shows that micronutrient nourishment (specifically protein, iron and zinc) has declined from the pressure of increased agricultural production of high-yield cereals with lower nutritional content (DeFries et al. 2015). Thus, it is important not only to ensure adequate calories, but the right type of foods.
The actual daily requirements can be set at a national level. The Food and Agricultural Organization (FAO) supports the use of a reference set of calorie intake requirements for men and women, on the basis of which deviations can be calculated for differences in age, and activity level (FAO 2001). Many countries have public health institutions that publish dietary guidelines for total calorie intake, and in some cases for micronutrients.
Having cold storage avoids risks of ill health from food-borne diseases and discomfort related to the time spent preparing and purchasing food items. Women usually bear this burden, in addition to the tasks of collecting water and cooking fuel. The extent of discomfort is contingent on a number of factors, including climate and diet,Footnote 10 but also access to markets. In many urban areas, where fresh food can be purchased on a daily basis, it is not easy to argue that refrigerators are universally essential, or that they always avoid extreme discomfort. However, given that the empirical support (see below) indicates an overwhelming desire to own a refrigerator, cold storage merit inclusion at least on the basis of being an overwhelmingly desired satisfier with no substitutes (See Sect. 1).
Empirical Support Almost 100% households own refrigerators in developed economies. In urban areas of select emerging economies (China, India, Brazil, South Africa), electricity access and refrigerator ownership has already, or is trending towards, saturation at over 90% penetration above a certain income threshold (See Table 3, in the Supplementary material).
Universal satisfier Durable homes that are resilient to severe climate and disease-carrying vectors.
Household requirements Solid roof and walls: brick, wood, concrete, or cement/steel construction.
Rationale Safe shelter (SDG 11.1) is, like food, a universally accepted goal of development policy, and a component of multi-dimensional poverty indicators. However, its formulation equally widely lacks specificity.
The UN Habitat places sufficient space and durable housing as its main priority for moving people out of slums in urban areas.Footnote 11 Sturdy construction protects from inclement weather, and therefore provides basic physical security.
Universal satisfiers (a) Minimum floor space; (b) adequate lighting; (c) basic comfort (bounded range of temperature and humidity in inhabited spaces); (d) adequate, accessible water supply; and (e) safe waste disposal.
Household requirements (a) Minimum of 30 m2 and 10 m2 per additional person, above three members; (b) electrical lighting (c) modern heating/cooling equipment, if necessary to remain within the comfort conditionsFootnote 12; (d) Adequate, reliable water supply (minimum of 50 L per capita per day) from an accessible water sourceFootnote 13; (e) in-house improved toilets.Footnote 14
Collective requirements The provision of the above household amenities may require the presence of a backbone infrastructure, for electricity, water and sanitation. The industrial organization and technology for this infrastructure depends on location and prevailing norms, and therefore need to be decided locally. For instance, today centralized electricity grids at a national scale provide electricity access, but water and sanitation typically fall within state- or municipal jurisdiction. The technology for sanitation may differ depending on cultural norms.
Rationale Overcrowding can lead to a number of health risks (e.g., related to sanitation), and less visible emotional stresses from lack of privacy and personal freedom. The amount of sufficient space should be decided at a local level. However, as a guide, it is worth considering national guidelines for minimum living space in affluent, but densely populated, countries. For instance, in Taiwan, recommended minimum living space ranges from 7 to 13 m2 per person, depending on number of members. In Korea, the minimum standard is 12 m2 for one person, and 8–10 m2 for each additional member. In previous work, we suggest this threshold should be closer to 10 m2/cap, which is the actual floor space to which middle class Indian homes plateau (Rao and Baer 2012). We additionally consider that homes have shared spaces—bathrooms and kitchen—that don’t scale with household size, but necessitate a minimum floor space. China’s average home size urban (rural) areas of ~32 (37) m2 offers another potential benchmark,Footnote 15 since families are typically small (due to the historical one-child policy), and living standards on average in China are likely to reflect an aggregation of a broad range of population densities and living conditions.
The lighting and space conditioning standards speak to habitability, and the avoidance of extreme conditions that may cause extreme discomfort or, in the worst case, death. The risk of these outcomes would vary with the severity of climatic conditions and with people’s vulnerability (e.g., elderly may have lower tolerance than youth). Similar to nutrition, further thresholds of exposure (e.g., maximum degree-days outside the comfort zone, or humidity levels) and vulnerability would have to be established for countries based on average population group characteristics and climatic conditions. There are many available references for defining a comfort zone, such as national guidelines on workplace occupancy conditions (e.g., US ASHRAE 55).Footnote 16 These can be adjusted for peoples’ adaptive preferences in different climatic conditions (Nicol 2004).
Water supply and sanitation, like food, have been examined extensively in public health and development policy. Gleick (1998) suggests that 50 l per capita per day is a minimum for all human ablutions. The World Bank has indicators for both improved water and sanitation, which provide useful guides for the quality and accessibility of these services. We adopt the World Bank’s indicator for improved sanitation and water source. In-house or accessible water supply obviates hours of labor that typically women undertake to collect water. Improved and accessible sanitation is essential not only to avoid the spread of disease from open defecation, but also to provide safe conditions for women.
Universal satisfier (a) Sufficient clothing to achieve basic comfort (as defined above) in prevailing climatic conditions; (b) access to washing machines.
Household requirements A certain amount of cloth (m2) with adequate materials catered to local climate;
Collective requirements Minimum number of shared washing machines per 1000.
Rationale As with food and shelter, clothing is to our knowledge an integral element of all poverty indicators, but also relatively unspecified. Clothing is also a feature of human life that is deeply embedded in culture and tradition. This makes it a clear candidate for further specification through local participatory methods. The only feature of normative importance is that these clothing are sufficient for daily activity in local climatic conditions.
Washing clothes is essential for basic hygiene. The need for washing machines is a matter of avoiding extreme discomfort from excessive manual labor. However, washing machines may be shared by number of households. In urban areas, shared facilities in apartment buildings and communities is already common practice. In rural areas, where homes are much more dispersed, sharing facilities can become a nuisance. However, since we aim to cater to the norm, not the exception, we eschew individual household entitlements to washing machines.
Empirical Support In most developed countries, most households have washing machines. However, communal washing facilities are common in urban areas of many countries, including the United States, where only 82% of homes have washing machines (Table 3, in the Supplementary material).
Universal satisfier Sufficient and accessible preventive and curative health care facilities.
Collective requirements Minimum physicians per 1000 people (possible range of 1.5–1.7); and minimum national health expenditure (possible range of PPPFootnote 17$~450–700 per cap).
Rationale Typical health outcomes in poverty indicators, such as life expectancy and infant mortality, offer little insight on the needs for health care. Although good health depends first on adequate nutrition and hygienic conditions, in reality, humans inevitably face disease, accidents, and other health hazards. Medical care is critical to prevent disease (e.g., vaccines), provide child care, and provide basic curative care. In order to provide these basic services, there needs to be sufficient health posts within reach of the population, with adequate facilities in each (e.g., cooling for medicines, electricity for X-rays) and qualified staff. These conditions are by no means sufficient to ensure a high quality of health care, but can be considered necessary.
But how should a minimum set of material conditions be determined? Health care services are necessary to reduce morbidity, avoid premature death and care for the elderly (palliative care) as they lose functioning capability. All these characteristics of a healthy society are well represented by average life expectancy, which is the primary measure of health in poverty measures, such as the HDI, and the more recent SPI. There is indeed a positive relationship between the resources committed to a health care system and average life expectancy, albeit with significant variation, and with diminishing returns beyond a point (See Supplementary material). This suggests that defining a DLS requires selecting a threshold for life expectancy. There is, however, no known normative basis to define a minimum length of a life.Footnote 18 Subjective preference isn’t useful either, because people generally aspire to live longer. Rather than seeking a normative threshold, we instead select this threshold based on where empirically we find that resources cease to have a positive effect on life expectancy. Based on extensive empirical analysis of the correlation between life expectancy and a number of different indicators of health care resources, including per capita national expenditure, we find that health care expenditure is correlated with life expectancy (LE) (see Supplementary material) in a certain range, ~70–75 years, but not very much below (where improvements in LE require few resources) or above (where increasing health care system resources has little effect on improving LE).
On this basis, we propose that societies require a minimum health expenditure, to sustain average life expectancy of 70–75 years. The suggested expenditure per capita (and reference life expectancy) is only a guide—individual societies may customize this value based on specific features of their health care system. We also found that the number of physicians (specifically, ~1.5–1.7 per 1000) also correlates to life expectancy. However, since the number of physicians doesn’t raise particular material requirements (doctors don’t eat more calories than people of other professions), we focus on health care sector expenditure as the primary metric for a DLS.
Empirical Support We estimate an annual expenditure of $450–700 per capita, corresponding to the average cost of the more efficient half of countries that have achieved a life expectancy of >65 years (and infant mortality of <15 deaths per 1000 live births) and >74 years (and infant mortality of <25). One caveat, however, is that it is unclear to what extent these expenditures include preventive health care or whether the latter correlates with overall health care costs. See Supplementary material for details.
Universal satisfiers Maximum particulate matter (PM) concentrationFootnote 19; This is a unique satisfier, since it is the restriction of a ‘bad’ material—particulate matter—which is a by-product of other commodities, including some that may be part of a DLS. This requirement, therefore, constrains the technologies used to meet other DLS.
Household requirements Modern cook stove, using gaseous fuel or electricity; modern heating/cooling equipment. Having a clean environment as part of decent living is echoed in D&G’s intermediate needs, and in the SPI and IDM indicators, but without further elaboration. According to the Global Burden of Disease, household air pollution (typically from burning biomass) is the third highest health risk factor, leading to over 4 million premature deaths per year (Lim et al. 2012), who are mainly women and children. Its avoidance requires that homes cook stoves and heating equipment run on liquid or gaseous fuels, rather than burn solid (biomass) fuels.
Collective requirements Ambient air pollution from other sources, including industry and transport, also contribute to health risks. This implies that the transport choices offered as part of mobility may have to include public transport in urban areas, and possibly even restrict engines to electric and other non-polluting technologies. The extent of these restrictions would be highly context specific, and therefore have to be determined at the local level.
Universal satisfier Adequate schooling with adequate facilities and staff.
Collective requirements Adequate number of schools, equipped with space, teaching staff, facilities, and balanced curriculum.
Rationale The human interest in gaining knowledge and the need for compulsory education is well established, and included in all mentioned poverty indicators. The duration of required schooling is more ambiguous. With regard to the duration, most countries (69%) that have minimum requirements require between 9 and 12 years, while 21% require only primary schooling.Footnote 20 We choose the lower bound of the majority option for the DLS.
Quality of education is, however, difficult to measure. Unlike with health care, there isn’t a clear relationship between educational attainment (or teacher absenteeism) and education spending. These factors are set aside for future research.
Information and Communication
Universal satisfier Household access to information and communication services.
Household requirement One phone per household, one television/computer monitor per household;
Collective requirement Accessible communication and television/internet infrastructure.
Rationale The importance of social and political engagement for human flourishing is found in all accounts of basic justice (Alkire 2002), and even in international human rights, as discussed earlier. Information services provide knowledge about society that enables people to critically engage as political participants.Footnote 21 Access to information can even be considered part of learning, when more broadly construed as the acquisition of knowledge about the world and society.Footnote 22 Such knowledge cannot be individually acquired without access to information services. The IDM and SPI include phone and internet access.
Technology plays a strong part in determining the medium of such access. As such, the specific satisfiers of this constituent of DLS is very much a product of the current times, and of our foreseeable future. For instance, it can be argued that people need have only newspapers for information. There is an element of conformity to globalized consumptive patterns inherent in the choice of cell phones and devices to access the Internet. However, these new technologies may indeed become essential to access these types of services, because they render older technologies obsolete and unavailable. Furthermore, even if alternatives do not die out, they are not able to provide the same level of access to information, which would lead to significant disparities in access to information, and therefore unequal enjoyment of basic rights to participation as equals in society.
Access to communication services is distinct from access to information, in that it entails the use of devices that enable interactive communication with other people, which is important for people to feel a sense of belonging and membership in community.
Empirical Support Almost 100% households own TVs and phones in developed economies. In urban areas of select emerging economies (China, India, Brazil, South Africa), ownership has already, or is trending towards, saturation at over 90% penetration above a certain income threshold.
Universal satisfier Access to adequate mobility options. ‘Adequate’ refers to the availability (within a certain distance from home) of motorized transport. Notably, adequate mobility can be provided with public transport. There may be exceptions in rural areas, which would have to be determined at a local level.
Collective requirements Adequate public transit in urban areas and road infrastructure to support access to paved road and motorized transport for all. In sparsely populated remote areas only, household ownership of vehicles may be necessary.
Rationale The importance of transport is understated in the literature. The MPI includes a vehicle, but only among a list of substitutable assets that comprise a living standard indicator. People universally have to either work away from their homes or access markets to sell wares for their livelihood. There is some evidence that through history people spend roughly the same amount of time on average (~1 h/day) traveling (Schafer and Victor 2000). It is just the mode of transport, and therefore the accessible distance, that has increased over time. If this is a fact, spending more time on traveling arguably can be construed as burdensome (and hence extreme discomfort). Without motorized transport of any kind, people’s lives would then be restricted to within a few kilometers of their home, which may lead to social exclusion, and restrict opportunities to participate in society, by way of selling wares, traveling for leisure, or learning about other societies.
The quantity of infrastructure that is required to provide everyone access is as far as we know an unaddressed research question. Future empirical investigation in this direction is necessary.
Empirical Support In developed countries, car ownership is often <85% and decreasing in urban areas. Vehicle ownership is consistently higher in rural areas, likely due to lack of alternatives.
Freedom to Gather/Dissent
Universal satisfier Adequate and safely accessible public spaces.
Collective requirements Minimum public space per 1000 inhabitants (with adequate facilities to ensure safety, such as lighting at night).
Rationale Adequate public space prevents overcrowding, and is important to foster a sense of freedom, for the pursuit leisure activities, and to congregate for political and social activities. This is particularly important in densely populated urban areas. This is also an SDG (11.7), which emphasizes the need for such spaces for women, children, elderly and disabled people. Here too, there is no guidance available in literature for the amount of space. However, there should be ample empirical evidence from which to develop reasonable benchmarks in further research.