Measuring Poverty: Beyond Income and GDP

How do we decide who counts as poor? The answer is not as obvious as it sounds. For decades, governments and global institutions drew a single line based on income or spending, counted everyone below it, and called the rest “not poor.” But a household can earn just above that line and still lack clean water, schooling, or basic healthcare. This gap between what income measures and what poverty actually feels like has pushed economists and policymakers toward richer, more honest ways of counting deprivation. Understanding how poverty is measured is the first step to understanding why so many people remain trapped in it even as economies grow.

The income line: A simple idea with a long history
How India draws its own line
Why GNP per capita is a misleading scorecard
Amartya Sen and the shift to capabilities
The Human Development Index
Counting many deprivations at once: The MPI
What the data reveals
Why the way we measure poverty matters

The income line: A simple idea with a long history

The oldest and most widely used approach treats poverty as a shortage of money. You set a threshold, called the poverty line, and anyone living below it is counted as poor. The proportion of people below this line is the head count ratio, the headline number you usually see in news reports.

Globally, the World Bank maintains an international poverty line to compare extreme poverty across countries. This line has been revised many times as prices change. It started at $1 a day in 1985 prices, became $1.08 using 1993 purchasing power parity, then $1.25, then $1.90, and most recently $3.00 per person per day using 2021 PPP figures. The line is adjusted using purchasing power parity (PPP), which accounts for the fact that the same dollar buys far more in a poorer country than in a richer one. The goal is to keep the line at roughly the same real standard of living everywhere, so a poor person in one country can be meaningfully compared with a poor person in another.

The strength of the income line is that it is simple, intuitive, and easy to track over time. Its weakness is that money is only a means to an end. A person can have a little cash but no access to a school, a clinic, or a toilet, and the income line will not capture any of that.

How India draws its own line

Most countries set their own national poverty lines, and India is no exception. Indian poverty lines have traditionally been built around the cost of a minimum basket of goods, originally tied to a calorie norm. The most recent official estimate uses the Tendulkar Committee methodology, which pegged the poverty head count at 21.9% in 2011-12, with rural poverty higher than urban poverty.

This line drew heavy criticism for being set too low. The Tendulkar line worked out to roughly Rs 27 a day in rural areas and Rs 33 a day in urban areas, figures many argued were impossible to actually live on. A later expert group under C. Rangarajan proposed higher lines, Rs 972 per month in rural areas and Rs 1,407 in urban areas for 2011-12. These would have pushed the count of poor people up by roughly 100 million, but the Rangarajan recommendations were never officially adopted. As a result, India has had no fresh official consumption poverty estimate for years, a striking gap for a country of its size.

Why GNP per capita is a misleading scorecard

If income measures matter, why not just track a country’s total income and divide it by population? This is exactly what Gross National Product (GNP) per capita does, and it is often used as shorthand for a nation’s average standard of living. The problem is that an average hides everything interesting about how that income is shared.

Imagine national income doubling. On paper, GNP per capita rises and the country looks twice as well off. But if almost all of that new income flows to the richest 10% while the poorest 40% see little change, poverty has barely moved. A rising average can coexist with stagnant or worsening conditions at the bottom. This is why growth in GNP does not automatically translate into poverty reduction. The distribution of income matters at least as much as its total size.

This insight explains a puzzle that recurs in global poverty data. The world economy has grown enormously over recent decades, yet large numbers of people remain poor. The World Bank estimates around 839 million people lived in poverty in 2024 by its updated standard. Growth helps, but growth alone, unevenly shared, leaves millions behind. Averages reassure governments while masking the lived reality of the deprived.

Amartya Sen and the shift to capabilities

The deepest challenge to income-based thinking came from the economist and philosopher Amartya Sen. Sen argued that poverty should not be understood as a lack of income but as a lack of capabilities, the real freedoms a person has to live a life they value.

In Sen’s capability approach, what matters is not how much money someone holds but what they can actually do and be. Can they be well nourished? Can they read and write? Can they participate in their community without shame? Income is only useful insofar as it helps people achieve these functionings. Two people with identical incomes can have very different real freedoms, depending on their health, their environment, and the social barriers they face. A disabled person, for instance, may need far more income to reach the same quality of life, so counting cash alone tells an incomplete story.

The Human Development Index

Sen’s ideas, developed alongside the economist Mahbub ul Haq, gave rise to one of the most influential alternatives to GDP-based measurement: the Human Development Index (HDI), introduced by the United Nations in 1990. The HDI combines three dimensions into a single score: a long and healthy life measured by life expectancy, knowledge measured through education, and a decent standard of living measured by income per capita.

Crucially, the HDI uses the logarithm of income to reflect a basic truth: an extra rupee means far more to a poor person than to a rich one. By building health and education directly into the score, the HDI refuses to let national wealth stand in for human wellbeing. The state of Kerala in India is the classic illustration. Despite a relatively modest per capita income, Kerala achieves high literacy, long life expectancy, and strong social indicators, demonstrating that human development can outpace income when public investment in health and education is strong.

Counting many deprivations at once: The MPI

The capability approach eventually produced a tool that directly measures multiple deprivations a household faces, rather than inferring them from income. This is the Multidimensional Poverty Index (MPI), built using the Alkire-Foster method developed at the University of Oxford. The global MPI is jointly published by the Oxford Poverty and Human Development Initiative and the UNDP.

Instead of asking only “how much do you earn,” the MPI asks whether a household is deprived across a range of everyday essentials. India has built its own National MPI, with NITI Aayog as the nodal agency. The National MPI measures deprivation across three equally weighted dimensions: health, education, and standard of living. These are captured through twelve indicators, including nutrition, child mortality, maternal health, years of schooling, school attendance, cooking fuel, sanitation, drinking water, electricity, housing, assets, and bank accounts.

A household is identified as poor only if it is deprived in a certain share of these weighted indicators at the same time. This captures something income never could: the overlapping nature of disadvantage. A family without electricity often also lacks clean cooking fuel, sanitation, and adequate nutrition, and the MPI counts these joint deprivations directly rather than guessing at them from a paycheck.

What the data reveals

The multidimensional lens has produced encouraging findings for India. A NITI Aayog discussion paper estimated that 24.82 crore people escaped multidimensional poverty over a nine-year period. Deprivation fell across all twelve indicators, with the largest absolute declines in populous states. This kind of granular, indicator-by-indicator tracking lets policymakers see exactly where progress is happening and where it is stalling, something a single income line could never reveal.

It is worth noting that the MPI is a measure of deprivation, not a replacement for an income poverty line. Both tell part of the story. Income measures track purchasing power and are easy to compare over time, while the MPI captures the texture of deprivation in daily life. Read together, they give a far fuller picture than either alone.

Why the way we measure poverty matters

Measurement is never a neutral technical exercise. The line you draw decides who receives help, how programmes are funded, and whether a government can claim success. A poverty line set too low makes poverty appear smaller and lets policymakers declare victory prematurely. A measure that ignores health and education can hide suffering behind a healthy growth rate.

This is why the shift from income alone toward capabilities and multidimensional measures is so significant. It reflects a changing understanding of what poverty actually is: not merely an empty wallet, but a constrained life. When we measure deprivation directly, we are far more likely to design policies that expand real freedoms, build schools and clinics, ensure clean water, and reach the people who need help most. The questions we ask in measurement shape the answers we deliver in policy.

What do you think? If India were to adopt a single official measure of poverty tomorrow, should it rely on an updated income line, a multidimensional index, or some combination of both? And when a country’s economy grows but its poorest citizens see little change, what does that tell us about how we have been measuring success all along?

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Table of Contents

The income line: A simple idea with a long history 🔗

How India draws its own line 🔗

Why GNP per capita is a misleading scorecard 🔗

Amartya Sen and the shift to capabilities 🔗

The Human Development Index 🔗

Counting many deprivations at once: The MPI 🔗

What the data reveals 🔗

Why the way we measure poverty matters 🔗