There were 1738, 1768, and 1761 male twins with complete latent factor PGD scores at times 1 through 3 respectively which represented 73% to 75% of the eligible sample from the previous interview (N=2368). Complete CU data were available from 1781 subjects at each time period. Age ranged from 24 to 62 years (μ = 40.3 years, σ2 = 9.1 years). Standardized Cronbach alpha coefficients for the PGD items at times 1 through 3 were 0.90, 0.87 and 0.87 respectively. As reported elsewhere (27), PGD test-retest correlations for the three time periods (based on 141 subjects interviewed on average of 29 days apart) were 0.81, 0.78 and 0.73 respectively. Age adjusted retest correlations for CU were 0.97, 0.94 and 0.94 at times 1 through 3 respectively.
