What makes these countries the happiest in the world? Here's the data evidence

World Happiness Report 2015 measures happiness levels for countries around the world by taking national level average scores for subjective well-being as reported by respondents.

Rediff Labs compared the happiness levels of each country with its Human Development Index and its Peace Deficit Index.

We found that Happiness is highly correlated with the Human Development Index of a country.

The Human Development Index as reported by the United Nations Development Programme includes measures for three parameters -- Long and healthy life (Life expectancy index), Knowledge (Education Index) and A decent standard of living (GNI Index).

We also found that happiness is negatively correlated with peace deficit.

Peace deficit data taken from by the Institute of Economics and Peace takes into account 22 indicators, which include ongoing domestic and international conflicts, societal safety and security and militarisation of the country.

The data above proves that factors like good health, education and income of a nation and peace are indeed closely tied to the happiness of its citizens.

For more data driven journalism, check out Rediff Labs.