Subjective well-being reflects the happiness of citizens and includes whether they believe and feel that their lives are desirable, satisfying, and rewarding. It is a key indicator of national quality of life – that is the extent circumstances in a nation are desirable – in addition to other economic and social indicators. It is important for societies to monitor subjective well-being because it reflects people’s experience of the quality of life due to desirable conditions such as good social relationships, economic prosperity, and health. However, there is also causation in the other direction in that happy people are likely to be friendlier, healthier, more cooperative, and better citizens. Furthermore, they are more likely to be successful and productive at work, and are likely to earn more money. In other words, happiness leads to circumstances associated with a better quality of life. The benefits of happiness generalize to the societal level in that happy societies are on average healthier and have higher social capital. Therefore, it is essential for societies to monitor subjective well-being or “happiness” not only because the measures of happiness broadly reflect the quality of life in the society, including circumstances beyond money, but also because they assess a characteristic that helps the society function effectively. Happiness can no longer be viewed as a luxury; we now know it is essential for quality of life. Although other facets of quality of life can be measured, such as capabilities, subjective well-being reflects the influence of these in people’s lived experience. Furthermore, subjective well-being is a crucial societal resource in producing good outcomes.