Xuxi Zhang

Internal Consistency Table 2 presents the internal consistency of the TFI. The Cronbach alpha of the full TFI and the physical, psychological and social domains was 0.74, 0.70, 0.52 and 0.29 respectively in the total population. The Cronbach alpha of the full TFI was ≥ 0.70 in each country. The Cronbach alpha of the physical domain was >0.70 in Croatia and the Netherlands, but varied between 0.60 and 0.68 in the other 3 countries. The Cronbach alpha of the psychological domain varied between 0.38 and 0.55 and that of the social domain between 0.22 and 0.43. Convergent and Divergent Validity Table 3 presents the convergent and divergent validity of the TFI domains. In the total population and in each country, the physical domain correlated significantly with the SF ‐ 12 PCS, GARS and GARS ‐ ADL. These correlations were higher than those between the psychological or social domain versus the SF ‐ 12 PCS, GARS and GARS–ADL, respectively. In the total population and in each country, the psychological domain correlated significantly with the SF ‐ 12 MCS and MHI ‐ 5. These correlations were higher than those between the physical or social domain versus the SF ‐ 12 MCS and MHI ‐ 5, respectively. In the total population and in each country, the social domain correlated significantly with the short ‐ JG. These correlations were higher than those between the physical or psychological domain and the short ‐ JG. Concurrent Validity Table 4 presents the concurrent validity of the TFI and its 3 domains. In the total population and in each country, the AUCs of the full TFI and the physical domain using physically frail or loss of independence as the criterion were excellent and using limited function as the criterion were acceptable to excellent. In the total population and in most of the countries, the AUCs of the full TFI and the psychological domain using poor mental health as the criterion were excellent. In Greece, the AUCs of the full TFI and the psychological domain were acceptable. In the total population and in most of the countries, the AUCs of the full TFI and the social domain using feeling lonely as the criterion were acceptable. In Croatia, the AUC of the social domain was not acceptable. 4 85 Reliability and validity of the TFI