Table 1.

Demographic characteristics of the sample

Measure	Dropouts	Returnees	Attrition replacements
N	225	995	170
Age, in years	Wave 1: 56.23 (2.5)*	Wave 1: 55.80 (2.5)	Wave 2: 62.67 (2.3)**
		Wave 2: 61.54 (2.4)
Education	13.70 (2.1)	13.87 (2.09)	13.44 (2.2)*
Age 20 GCA	59.95 (23.11)	61.40 (22.1)	54.27 (22.9)**
APOE-ε4+	58 (25.8%)	293 (29.4%)	37 (21.8%)

NOTE. GCA = general cognitive ability based on the Armed Forces Qualification Test (AFQT). Standard deviations (SDs) are reported in parentheses (except when reporting percentages).

NOTE. *P < .05 and **P < .001 significance of comparison with returnees.