How the comparison is scored

For each dimension, take the countries on this page that have a figure. The lowest figure in that set is scored 0 and the highest is scored 100, in a straight line between them. Where a lower raw figure is the better outcome — fewer homicides, a lower price level, lower unemployment — the line is flipped, so the lowest raw figure scores 100.

An index of 0 is the bottom of this set, not a zero in the source. Hungary’s Human Development Index, 0.870, is the lowest figure here, so its development index is 0. The United States homicide rate, 5.76 per 100,000, is the highest here, so Safety — fewer homicides score higher — is 0.

If every country that has a figure has the same figure, each of them scores 100. There is no spread to stretch.

Countries without a figure are not in the minimum or the maximum. Their absence does not move anyone else's score on that dimension.

A weight is an integer from 0 to 10. Zero leaves that dimension out of the result.

A country's result is the weighted mean of the dimension scores it actually has, using only the weights above zero. In symbols: the sum of (score × weight) divided by the sum of those weights. A missing figure is not in the numerator and not in the denominator. The list says which figures were missing, and the result is then not comparable to a country that had every figure, in the sense that it rests on a different set of weights. The page shows the set.

A missing figure is not replaced with zero, with the average of the other countries, or with a guess. If every weight that remains is zero, that country has no result.

The climate figure is the national mean of surface air temperature for 1991–2020, in degrees Celsius. The score is closeness to the temperature you set on the slider. Closeness is then stretched from 0 to 100 in the same way as the other dimensions. The country nearest your number scores highest. The country farthest from it scores lowest.

The slider starts at 15 °C. That is a starting point, not a finding that 15 °C is a good climate. Warmer is not treated as better, and cooler is not treated as better.

Scores are relative to the countries on this page, not to the world. Adding or removing a country changes the 0 and the 100.

The year on a figure is the year of that observation. Series are not aligned to one year, and countries inside one series are not always in the same year. The edition of the dataset is named with the source.

Homicides are not a peace index and not a crime index. A low rate can sit beside risks this page does not measure.

GDP per capita is a mean at purchasing-power parity. In Ireland, Luxembourg, and Singapore it includes profit booked by foreign firms, so it is a weak guide to a typical paycheck. Purchasing-power parity already adjusts for the local price level; the separate cost figure is that price level on its own.

The cost figure is the World Bank's price level of GDP: the PPP conversion factor divided by the official exchange rate, for the latest year in which both are published. The United States is 1. The World Bank's own ratio series (PA.NUS.PPPC.RF) is archived and the data API no longer returns it, so this page calculates that defined ratio and keeps both inputs beside the result. It is a whole-economy price level, not rent in one city. The ratio is rounded to four decimal places after the division. The inputs are not rounded first.

The climate number is a national land mean. Canada's north pulls the country mean well below the temperature of its cities. One annual mean does not describe seasons.

Unemployment is an ILO model of the labour force, not a count of jobs offered to someone arriving from abroad.

The happiness figure is a three-year average of one life-evaluation question, the Cantril ladder. The 2025 column in the 2026 report is the average of the 2023–2025 waves. It is not a forecast.

The Human Development Index mixes health, schooling, and income. UNDP recalculates the whole series when the report is updated, so a value in this edition is not comparable with a value printed in an older report.

Changing the weights changes the order. The order is not a property of the countries alone.