Table 6.

Content Validity, Face Validity, Structural Validity, and Known-Groups Validity of the TFI

Authors	Content Validity
Gobbens et al1	Determined by representatives of professional disciplines and people aged ≥75 years
Theou et al46	The TFI records items referring to limitations in self-rated health, nutrition, mobility, energy, cognition, mood
Andreasen et al48	Determined by interviewing frail community-dwelling older people: the majority of important frailty items were covered by the TFI; pain, sleep quality, meaningful activities and spirituality are not present in the TFI
Face Validity
Gobbens et al1	Checked by participants at geriatric meetings
Andreasen et al8	A pretest was performed by cognitive interviewing. The TFI was translated and adapted in such a manner that it can be implemented and further tested in clinical practice
Structural Validity
Vrotsou et al14	Confirmatory factor analysis) (CFA) showed that fit indexes of a second-order model of three factors (frailty domains) were acceptable
Known-Groups Validity
Vrotsou et al14	Total and physical frailty scores differentiated well between frail and non-frail people defined by the GFST and the SPPB

Abbreviations: GFST, Gérontopôle Frailty Screening Tool; SPPB, Short Physical Performance Battery.