" measures like GDP per person give only a rough reflection of the overall level of wellbeing of an individual or a nation. But for sustainable development we are interested in raising human wellbeing, not just in raising income, still less in a mad race for more riches for people who are already rich. Therefore, it is important to ask how we can best measure wellbeing (or life satisfaction) beyond GDP per capita. "

― Jeffrey D. Sachs , The Age of Sustainable Development