Exploring and explaining the "Santa Claus effect": cross-sectional study of jollity in 21 European countries.

BACKGROUND: Christmas "is the season to be jolly" but, despite many recent studies of happiness and wellbeing, the population distribution of jollity is unknown.

AIMS: To assess levels of jollity across Europe, hypothesising the existence of a "Santa Claus effect" whereby Mr. Claus, a long-established resident of Scandinavia, increases jollity through his social network.

METHODS: Cross-sectional analysis of data from 37 966 participants in the European Society Survey (Round 7, 2014/2015) across 21 European countries.

RESULTS: Jollity has independent associations with satisfaction with health and income, male gender, younger age, and country of residence. Each one-point increase in satisfaction with health (on a 5-point scale) corresponds to a 0.79-point increase in jollity (23-point scale); each one-point increase in satisfaction with income (4-point scale) corresponds to a 0.76-point increase in jollity. Switzerland is the jolliest country in Europe.

CONCLUSIONS: The jolliest European is likely to be a young Swiss male who is satisfied with his income and health. If there is a Santa Claus effect acting to increase jollity, it probably acts not just in Scandinavia but across Mr. Claus's broad network of contacts and admirers in many countries.