FIGURE 2.

Item‐to‐item correlation matrices. The neuropsychological item to item correlation matrices: a, entire ADNI sample correlation matrix; b, NIMROD correlation matrix; c, NUS correlation matrix; d, BACS correlation matrix; e, ADNI correlation matrix for subsample who were cognitively normal at baseline; f, AIBL Validation cohort. We observed highly reproducible loadings of the real variables and the imputed ADNI composites across each cohort, ADNI‐Mem versus C/H/RAVLT total (reference ADNI: R ² = 89.3%; NUS: R ² = 90.5%; NIMROD: R ² = 94.6%; BACS: R ² = 84.5%; AIBL: R ² = 92.6%) and ADNI‐EF versus log(Trails B) (reference ADNI: R ² = 85.1%; NUS: R ² = 89.6%; NIMROD: R ² = 89.9%; BACS: R ² = 78.7%; AIBL, Trails B not collected). ADAS‐Cog, Alzheimer's Disease Assessment Scale Cognitive subscale; ADNI, Alzheimer's Disease Neuroimaging Initiative; AIBL, Australian Imaging, Biomarker & Lifestyle Flagship Study of Ageing; BACS, Berkeley Aging Cohort Study; BNT, Boston Naming Test; CDR, Clinical Dementia Rating; DSPAN, Digit Span; (H/C/R)VLT, Hopkins/California/Rey Verbal Learning Tests; INECO, Institute of Cognitive Neurology Frontal Screening; k‐NN, k‐nearest neighbors; LM, Logical Memory; MINT, Multilingual Naming Test; MOCA, Montreal Cognitive Assessment; NIMROD, Neuroimaging of Inflammation in Memory and Related Other Disorders study; NUS, National University of Singapore; RCFT, Rey Complex Figure Test; WAIS, Wechsler Adult Intelligence Scale