Key Approaches to Understanding Developmental Disparities

Ask ten people what “development” means and you will get ten different answers. For decades, economists settled the question with a single number: Gross National Product. If GNP was rising, a country was assumed to be doing well, regardless of who benefited and who was left out. Extension education scholars and development economists eventually pushed back on this narrow view, arguing that real development has to be measured through the lived experience of people, not just the size of the economy. This is where different approaches to studying indicators of development come in, each offering its own lens on how disparities between and within nations can be identified and understood.

Why a single measure of development falls short 🔗

Income-based measures like per capita GNP tell us how much wealth a country generates, but they say nothing about how that wealth is distributed. A nation can post impressive growth figures while large sections of its population remain illiterate, malnourished, or excluded from basic services. Development thinkers from the 1960s onward recognised that economic growth and human wellbeing are not the same thing, and that measuring disparities required looking at social, political, and physical indicators alongside economic ones. Four approaches became especially influential in shaping how researchers and extension educators study these gaps: the UNRISD approach, the Adelman and Morris approach, the Physical Quality of Life Index, and the Human Development Index.

The UNRISD approach: development as an interconnected system 🔗

The United Nations Research Institute for Social Development (UNRISD) was set up in 1963 with a mandate to study the social dimensions of development rather than treating it purely as an economic exercise. Its early research, led by Donald McGranahan through the 1960s and 70s, focused on building indicators that captured nutrition, health, education, and housing conditions, not just national income accounts.

The core idea behind the UNRISD approach is that social, economic, and political factors interact continuously and cannot be studied in isolation. A rise in literacy affects political participation. Political stability affects investment and employment. Employment affects nutrition and health outcomes. UNRISD’s method involved identifying a core set of indicators, such as education levels, health infrastructure, housing, and employment, and studying how they move together across countries and time periods. This systemic view was one of the earliest formal attempts to argue that measuring disparities required a basket of interconnected indicators rather than one master number.

The Adelman and Morris approach: factors beyond income 🔗

Economists Irma Adelman and Cynthia Taft Morris took this idea further in their influential 1967 and 1973 studies. Rather than relying on a handful of indicators, they used factor analysis, a statistical technique, to examine dozens of social, economic, and political variables across a large sample of developing countries. Their multi-indicator theory of development considered variables like literacy rates, the extent of urbanization, social mobility, mass communication, and the strength of political institutions, alongside conventional economic measures.

What made this approach distinctive 🔗

Adelman and Morris argued that development is not linear. Two countries with similar per capita income can have very different levels of social mobility, urban infrastructure, or political participation, and these differences explain why some populations experience deeper disparities than others despite similar economic output. Their work also found that the structure of a country’s educational system, whether it was broad-based or restricted to a narrow elite, strongly influenced whether income gains from growth actually reached the poor. This finding remains relevant to extension education discussions on marginalisation even today, since it links access to schooling directly with the distribution of development’s benefits.

Physical Quality of Life Index: a simpler yardstick 🔗

By the mid-1970s, development researchers wanted an index that was easier to compute and communicate than complex multivariate models. Economist Morris David Morris created the Physical Quality of Life Index (PQLI) for the Overseas Development Council, built on just three indicators: infant mortality rate, life expectancy at age one, and basic literacy rate.

Each indicator is scaled from 0 to 100 based on the best and worst levels recorded historically across countries, and the three scores are then averaged to arrive at a single PQLI value. The logic behind choosing these three indicators was practical. Nearly every country already collected this data reliably, and together, the three capture the outcomes of health, nutrition, sanitation, and education systems without needing income data at all.

Strengths and limitations of PQLI 🔗

PQLI’s biggest strength is that it reflects how widely development benefits are shared. A country cannot achieve high literacy and low infant mortality unless services reach a large share of its population, so the index indirectly captures distributional fairness. However, it ignores important dimensions like employment, housing quality, personal freedom, and income inequality itself, which limits how completely it can represent disparities on its own.

Human Development Index: the modern global standard 🔗

Introduced in 1990 by economists Mahbub ul Haq and Amartya Sen for the United Nations Development Programme, the Human Development Index (HDI) remains the most widely used composite measure of development today. It combines three dimensions: a long and healthy life, measured through life expectancy at birth; access to knowledge, measured through mean and expected years of schooling; and a decent standard of living, measured through Gross National Income per capita.

The HDI’s approach reflects a shift in thinking, from measuring development as economic output to measuring it as an expansion of people’s real choices and capabilities. Countries are ranked into four categories: low, medium, high, and very high human development, based on their composite score.

What HDI reveals about disparities in India 🔗

India’s own HDI trajectory illustrates why this index matters for studying disparities. According to the 2025 Human Development Report, India ranked 130th out of 193 countries, still placed in the medium human development category despite steady improvement over three decades. The report also highlighted a widening gap between low and very high HDI countries, showing that global disparities have grown rather than shrunk in recent years. Within India, states like Kerala consistently post significantly higher human development outcomes than states like Bihar or Jharkhand, showing that national averages can hide enormous internal disparities.

Bringing these approaches together for extension education 🔗

For those studying marginalisation and developmental disparities, no single approach tells the whole story. UNRISD’s systemic view reminds us that social, political, and economic factors cannot be separated. Adelman and Morris’s factor-analysis method shows how structural features like education policy shape who benefits from growth. PQLI offers a quick, health-and-literacy-based snapshot of distributional fairness. HDI provides a globally comparable benchmark that policymakers and international agencies still rely on.

India has also built on these traditions with its own tools. The National Multidimensional Poverty Index, developed by NITI Aayog along with UNDP and the Oxford Poverty and Human Development Initiative, measures deprivation across health, education, and standard of living using twelve indicators, and it is specifically designed to track disparities at the state and district level. This localised approach shows how the core logic of these older frameworks, look beyond income, use multiple indicators, and pay attention to distribution, continues to shape how disparities are studied and addressed today.

What do you think? Which of these approaches do you think captures developmental disparities most usefully in the Indian context, a single composite score like HDI, or a detailed multidimensional index like the National MPI? And do you think an index built in the 1970s, like PQLI, still has relevance for policymakers working on marginalisation today?

References

1. https://sdgs.un.org/un-system-sdg-implementation/united-nations-research-institute-social-development-unrisd-60338
2. https://documents1.worldbank.org/curated/en/625131468761704307/pdf/28737.pdf
3. https://www.encyclopedia.com/social-sciences/applied-and-social-sciences-magazines/physical-quality-life-index
4. https://www.undp.org/india/human-development-index-india
5. https://www.undp.org/india/press-releases/indias-human-development-continues-make-progress-ranks-130-out-193-countries
6. https://www.niti.gov.in/sites/default/files/2023-08/India-National-Multidimentional-Poverty-Index-2023.pdf