Table 3

Mean (95% CI) growth parameters for two-, three-, and four-class growth mixture models of living standards (LS) trajectories with age

Est. population %†Intercept (I)Linear slope (S)Factor covariance (I-S)‡Description
Mean (95% CI)Variance‡Mean (95% CI)Variance‡Mean (95% CI)
Two-class model
 C21 87.425.4 (25.3 to 25.6)***11.8***0.1 (0.1 to 0.2) ***0.3***0.2 (−0.1 to 0.5)Good LS
 C22 12.612.4 (11.8 to 13.0)***11.8***0.8 (0.6 to 1.0) ***0.3***0.2 (−0.1 to 0.5)Hardship, ↑ LS
Three-class model (optimal model)
 C31 86.125.6 (25.4 to 25.7)***11.2***0.1 (0.1 to 0.2)***0.1***−0.1 (−0.2 to 0.0)Good LS
 C32 8.813.4 (12.6 to 14.2)***11.2***1.6 (1.4 to 1.7)***0.1***−0.1 (−0.2 to 0.0)Hardship, ↑ LS
 C33 5.112.4 (10.9 to 13.8)***11.2***−0.8 (−1.1 to −0.5)***0.1***−0.1 (−0.2 to 0.0)Hardship, ↓ LS
Four-class model
 C41 80.226.2 (26.0 to 26.4)***6.6***0.1 (0.1 to 0.2)***0.1***−0.0 (−0.2 to 0.1)Good LS
 C42 10.816.4 (15.5 to 17.4)***6.6***1.3 (1.0 to 1.5)***0.1***−0.0 (−0.2 to 0.1)Hardship, ↑ LS
 C43 5.617.2 (15.9 to 18.5)***6.6***−0.7 (−1.1 to −0.4)***0.1***−0.0 (−0.2 to 0.1)Comfortable, ↓ LS
 C44 3.46.7 (5.9 to 7.4)***6.6***0.3 (0.0 to 0.7)0.1***−0.0 (−0.2 to 0.1)Hardship LS
  • Data weighted by response characteristics; model intercept represents mean ELSI-SF score ages 63–64.

  • *P<0.05, **P<0.01, ***P<0.001.

  • †Design-weighted proportions.

  • ‡Partially restricted growth mixture model with between-class invariant variances and covariance.

  • ↓, decrease with age; ↑, increase with age; ELSI-SF, Economic Living Standards Index Short Form; LS, living standards.