Table 1.

Psychometric properties of the AD8

Psychometric property	Definition	AD8 characteristics
Concurrent validity	Correlation of the AD8 compared with ‘gold standard’ measures of dementia presence and severity (the CDR)	R = 0.75 (95% CI 0.63–0.88)
Construct validity	Correspondence of how well the AD8 measures theorized domains corresponding to CDR and neuropsychological tests. Demonstration of strong correlations (≥40%) support convergent validity, while low correlations (≤30%) indicate no relationship	R > 0.4 for memory, executive function, and activities of daily living; R < 0.3 for semantic memory and language function.
Internal consistency	Degree to which the AD8 is free from random error	Cronbach’s α = 0.86 (95% CI: 0.82–0.91)
Intra-rater reliability	Degree to which an instrument yields stable scores over time for the same respondent	Weighted κ = 0.67 (95% CI: 0.59–0.75)
Inter-modal reliability	Reproducibility of the AD8 across different modes of administration (in person versus telephone)	Weighted κ = 0.65 (95% CI: 0.57–0.73)
Inter-rater reliability	Percent agreement between two raters	Intraclass correlation coefficient = 0.82 (95% CI 0.55–0.92)
Discriminability	Effectiveness of the AD8 in classifying a CDR score of 0 (non-demented) versus a CDR score > 0.5 (demented) for different demographic characteristics, MMSE scores, CDR stages and clinical diagnoses	Area under the curve = 0.92 (95% CI 0.88–0.95)

AD8 characteristics are adapted from Galvin et al., 2006.