The Human Development Index (HDI) is a United Nations metric from 0 to 1 that evaluates a country's average well-being based on life expectancy, education levels, and gross national income per capita. According to the latest data from 2023, published in the 2025 Human Development Report, Iceland ranks as the best country with the highest global score of 0.972, closely followed by Switzerland and Norway. Conversely, South Sudan ranks as the worst country with the lowest score of 0.388, driven by