Which combination of measures is used in calculating the HDI?

• A. Life expectancy, mean years of schooling, and GNI per capita
• B. Life expectancy and GNI per capita only
• C. Life expectancy, education (mean and expected years), and GNI per capita (PPP)
• D. GNI per capita only

Answer: (C)

The HDI combines three broad areas of development: health, education, and living standards. Health is represented by life expectancy at birth, which signals how long people are expected to live and, indirectly, how healthy their environment and healthcare are. Education is captured with two indicators: mean years of schooling for adults and expected years of schooling for a child entering school. Including both measures reflects not only how much education people have already but also how much education the future generation is likely to receive. Living standards are measured by gross national income per capita adjusted for purchasing power parity (PPP), which normalizes income across countries so price level differences don’t distort comparisons.

So, using life expectancy, education (both mean and expected years), and GNI per capita in PPP is the way the HDI aggregates health, knowledge, and income into a single development metric. The other options miss one or more components or the PPP adjustment, which are essential to the HDI.