Table 3.
Test–Retest Reliability, Inter-Rater Reliability, and Parallel Forms Reliability of the TFI
| Authors | Test-Retest Reliability |
|---|---|
| Gobbens et al1 | Two weeks (Pearson correlation coefficient): total 0.90, physical 0.87, psychological 0.77, social 0.86 One-year period (Pearson correlation coefficient): total 0.79, physical 0.78, psychological 0.67, social 0.76 |
| Santiago et al7 | 7–10 days (Pearson correlation coefficient): total 0.88, physical 0.88, psychological 0.67, social 0.89. 7–10 days (simple agreement); items ranged from 0.63 (memory) to 1.00 (live alone, lack of support) 7–10 days (Kappa coefficients): five items had nearly perfect agreement (0.81–1.00), four items had substantial agreement (0.61–0.80) agreement, two items had moderate agreement (0.41–0.60), four items had fair agreement (0.21–0.40) |
| Coelho et al10 | 12–16 days: (Pearson correlation coefficient): total 0.91, physical 0.87, psychological 0.75, social 0.87. 12–16 days (simple agreement): items ranged from 0.78 (depression, anxiety) to 0.97 (living alone) 12–16 days (Kappa coefficients): ranged from 0.52 to 0.95 |
| Uchmanowicz et al50 | 10–14 days: (Kappa coefficient): a high level of agreement with regard to items was demonstrated with coefficients ranging from 0.96 to 1.00 |
| Freitag et al12 | 20 weeks (ICC): total 0.87, physical 0.85, psychological 0.75, social 0.84 |
| Dong et al13 | 10–25 days (ICC): total 0.88, physical 0.80, psychological 0.65, social 0.81 |
| Vrotsou et al14 | 7–14 days (simple agreement): item ranged from 0.77 to 0.99, except anxious (0.66) 7–14 days (Kappa coefficient): 0.98 (living alone), 0.23 to 0.34 (physical tiredness, anxious, coping, support) 0.46 to 0.57 (all other items, except unintentional weight loss) |
| Topcu et al15 | One week (ICC): 0.99 |
| Alqahtani et al52 | One week (ICC): 0.86 |
| Inter-rater reliability | |
| Topcu et al15 | Two observers on the same day (ICC): 0.99 |
| Parallel forms reliability | |
| Theou et al46 | Kappa coefficients: TFI and Frailty Index 0.52, Frailty Index based on Comprehensive Geriatric Assessment 0.52, Clinical Frailty Scale 0.38, Frailty Phenotype 0.37, Edmonton Frail Scale 0.27, FRAIL scale 0.27, Groningen Frailty Indicator (GFI) 0.50 |
| Dong et al13 | Kappa coefficients: ranged for TFI items and alternative measures from 0.12 (hearing problems)–1.00 (living alone) |
Abbreviation: ICC, intraclass correlation coefficient.