Characteristics of study subjects (n = 229,099).

Happiness is predicted by social relationships in general and contact frequency in particular. This study aims to examine if the relative importance of social contacts with the closest family/relative, friend, and neighbor in happiness changes with advancing age. We used data for all participants aged 19 years and older (n = 229,099) in the 2019 Community Health Survey, which measured the frequency of contact with the closest relative/family, neighbor, and friend among a representative sample of Koreans between August 16 and October 31, 2019. The Shapley value decomposition method was used to measure the relative importance of each predictor of happiness. Overall, contact frequency was positively associated with happiness (p