① The relationship between cash and contentment has consumed philosophers for millennia. "Happiness economics" is now a lively field of study.
② Today the United Nations releases the "World Happiness Report" to mark its "International Day of Happiness".
③ The event may seem risible, but the report is penned by academics and uses hard data from Gallup, a pollster, to rank 156 countries according to their average self-reported life satisfaction.
④ Nordic countries tend to be happiest; African ones the most miserable.
⑤ At first glance the relationship between GDP per person and self-reported happiness seems irrefutable.
⑥ But over time countries that get richer do not necessarily become more joyful.
⑦ This paradox, first observed by Richard Easterlin in 1974, has been hotly contested for years.
⑧ Take India and China. While GDP per person in both countries has broadly doubled over the past decade, their cheeriness has gone in opposite directions.
⑨ Working out precisely why that is could keep wonks happy for years.