Six measures across 187 countries — inequality, basic services, and the financial burden of illness.
Source: World Bank World Development Indicators and WHO/UNICEF Joint Monitoring Programme. Inequality is measured from household surveys run every few years, so those three views show each country's most recent reading with the year on hover — some are a decade old. The Gini index runs from 0, where everyone has the same income, to 100, where one person has it all; real values fall between roughly 24 and 63. Income shares are often clearer: what the richest tenth and the poorest fifth actually receive. "Safely managed" water and sanitation are stricter standards than "basic" — they require an improved source on the premises, available when needed and free from contamination. Out-of-pocket health spending is the share of health costs paid directly by households at the point of care, and it is the measure most closely tied to illness pushing people into poverty.
The Gini index is the standard inequality measure and it is nearly useless for communication. A value of 0.41 conveys almost nothing to a reader who does not already know the scale, and even people who do struggle to say what separates 0.38 from 0.45.
The income shares say the same thing in terms anyone can picture. The richest tenth of a population receive a certain percentage of all income; the poorest fifth receive another. Both views are here for that reason.
The hover panel goes further and divides one by the other. In the most unequal countries the richest tenth receive around ten times what the poorest fifth do — and since the tenth is half the size of the fifth, the ratio per person is roughly twenty to one.
That is the number to quote. It is exact, it comes from the same survey, and it needs no explanation.
Inequality comes from household income and expenditure surveys, which most countries run every three to five years and some far less often.
A strict year view would show almost nothing — fewer than eighty countries report in any single year. So the three inequality views show each country’s most recent reading, with the year given on hover.
This means the map compares surveys taken years apart. For countries where inequality has moved sharply, an older reading understates the current position. The year label is there so you can see which you are looking at.
Water, sanitation and health spending are modelled annually and keep their year buttons.
The water and sanitation figures use the stricter of two SDG standards, and the distinction matters.
A basic drinking water service means an improved source within a thirty-minute round trip. Safely managed requires an improved source on the premises, available when needed, and free from contamination. A household can have basic service and still be drinking unsafe water.
For sanitation, basic means an improved facility not shared with other households. Safely managed additionally requires that the waste is treated and disposed of safely — which many countries with near-universal toilet access do not achieve, because treatment infrastructure lags behind household provision.
Using the stricter standard produces lower numbers and a more honest map. Several countries that appear to have solved water and sanitation on the basic measure have not.
This is the share of total health expenditure paid directly by households at the point of care, rather than through taxation or insurance.
It is the closest available proxy for whether illness causes poverty. Where the figure is high, a serious diagnosis is a financial event as well as a medical one, and households sell assets, withdraw children from school or forgo treatment entirely.
The WHO considers anything above 20% likely to produce catastrophic health expenditure for some households; above 40% it becomes widespread. A substantial number of countries sit well above both thresholds.
Note that this is a share, not an amount. A country with low total health spending and moderate out-of-pocket share may still impose severe costs on households in absolute terms.
Related work:
Data from the World Bank World Development Indicators and the WHO/UNICEF Joint Monitoring Programme.