Table 1.

Descriptive statistics for measures entered into the bivariate dual change score model.

Measure	n	M	SD	Raw Score Range
Depressive Symptoms
Wave 1	1206	50.10	9.93	0 – 48
Wave 3	955	49.31	9.34	0 – 42
Wave 6	447	51.20	8.98	0 – 39
Wave 7	301	50.21	9.96	0 – 40
Wave 9	135	51.61	9.53	0 – 35
Perceptual Speed
Wave 1	1206	49.45	9.59	0 – 72
Wave 3	859	51.16	10.11	2 – 72
Wave 6	349	50.94	9.15	3 – 63
Wave 7	262	49.07	9.72	0 – 67
Wave 9	121	50.40	9.15	8 – 63
Covariates
Age	1206	77.88	6.30	65 - 98
Medical Conditions	1206	2.47	1.66	0 - 10
MMSE > 24	96	8.0%
Education < 15 years of age	579	48.0%

Note. Depressive symptoms and perceptual speed were assessed at baseline and after approximately two, eight, eleven and fifteen years. Depressive symptoms were assessed using the Center for Epidemiological Studies Depression Scale (Radloff, 1977). Depressive symptoms and perceptual speed scores were standardized to the T metric (M=50, SD =10) using the baseline sample. MMSE (Mini-mental Status Examination) was dichotomized as scoring less than 24, and 24 or more. Education information was limited to a dichotomized variable of leaving school before 15 years of age, or leaving at age 15 or later.