Test–retest reliability and validity of a single-item Self-reported Family Happiness Scale in Hong Kong Chinese: findings from Hong Kong Jockey Club FAMILY Project

Purpose Family happiness is one major theme of family well-being in Chinese culture. We investigated the reliability and validity of the single-item Self-reported Family Happiness Scale (SFHS-1) with the score of 0–10, based on two studies in Hong Kong Chinese. Methods Study 1 was a territory-wide population-based telephone survey ( n = 4038) conducted in 2016. Study 2 was a community-based family intervention program conducted during 2012–2013 ( n = 1261) to enhance family communication and well-being. Test–retest reliability of the SFHS-1 was assessed over 1 month in Study 2. Family APGAR (Adaption, Partnership, Growth, Affection, Resolve) Scale, Family Communication Scale, Subjective Happiness Scale, 12-item Short Form Health Survey Version 2, and 2-item Patient Health Questionnaire were used to assess the convergent and discriminant validities of the SFHS-1 in both studies. Multiple regression analysis was used to assess the incremental validity by identifying the additional contribution of the SFHS-1 score in predicting subjective happiness. Results The 1-month test–retest reliability assessed by intraclass correlation was 0.76. Family happiness was moderately to strongly correlated with family function, family communication, subjective happiness, mental health-related quality of life and depression, but weakly correlated with physical health-related quality of life. Furthermore, the score of the SFHS-1 added predictive power to mental health-related quality of life and depression in assessing subjective happiness. Conclusions Our results have shown the SFHS-1 as a reliable and valid measurement of family happiness in Hong Kong Chinese, suggesting SFHS-1 is highly practicable for future large epidemiological and community-based intervention studies.