Table 1.

Descriptive Characteristics of Participants With a Three-Assessment Measurement Burst Only at T2 (single burst) or With a Burst Assessment at Both T1 and T2 (double burst)

	M	SD	Age correlation
Single-burst participants
N	862	NA	NA
Age at T1	53.2	16.6	NA
Proportion of female	0.66	NA	−0.05
Years of education	15.7	2.7	0.21*
Self-rated health	2.1	0.9	0.14*
Retest interval	2.6	1.2	−0.03
Scaled scores (at T1)
Vocabulary	12.9	3.1	0.16*
Digit Symbol	11.5	2.8	0.10*
Logical Memory	12.1	2.9	0.17*
Word Recall	12.6	3.1	0.09
Double-burst participants
N	420	NA	NA
Age at T1	54.7	18.7	NA
Proportion of female	0.63	NA	−0.01
Years of education	15.7	2.6	0.21*
Self-rated health	2.3	0.9	0.14*
Retest interval	2.2	0.6	0.00
Scaled scores (at T1)
Vocabulary	13.0	2.9	0.11
Digit Symbol	11.6	2.8	0.18*
Logical Memory	12.0	2.8	0.21*
Word Recall	12.6	3.4	0.07

Note: The age range in the single-burst participants was 18–95 years and that in the double-burst participants was 18–91 years. Health was rated on a 5-point scale in which 1 represented excellent and 5 represented poor. Scaled scores have M of 10 and SDs of 3 in the normative samples (i.e., Wechsler, 1997a, 1997b). NA = not applicable.

*p < .01