TABLE 4

Mediation Effects for NSI Subgroup Models

MediatorTotal EffectDirect EffectIndirect Effect95% CI% Mediateda
ELBW survivors without NSI impairments
 Personal income models
  Overall IQ (WISC-R full scale)−16 871−12 848−4023*−87 886 to −15924
  WISC-R verbal IQ−16 871−13 618−3252*−6418 to −8719
  WISC-R performance IQ−16 871−14 206−2665−6281 to 95116
  Mathematical abilities (WRAT-R M)−16 871−13 107−3764*−7068 to −46022
  Academic abilities (WJ)−16 871−14 804−2066−4679 to 54512
 Full-time employment models
  Overall IQ (WISC-R full scale)−0.89−0.64−0.08−0.23 to 0.0731
  WISC-R verbal IQ−0.89−0.75−0.06−0.17 to 0.0623
  WISC-R performance IQ−0.89−0.68−0.06−0.21 to 0.0823
  Mathematical abilities (WRAT-R M)−0.89−0.70−0.06−0.19 to 0.0723
  Academic abilities (WJ)−0.89−0.83−0.02−0.09 to 0.058
ELBW survivors with NSI impairments
 Personal income models
  Overall IQ (WISC-R full scale)−18 664−11 836−6828*−13 397 to −26037
  WISC-R verbal IQ−18 664−13 701−4963−10 000 to 7427
  WISC-R performance IQ−18 664−13 593−5071−11 885 to 174227
  Mathematical abilities (WRAT-R M)−18 664−11 110−7554*−13 759 to −134940
  Academic abilities (WJ)−18 664−13 010−5654*−10 964 to −36330
 Full-time employment models
  Overall IQ (WISC-R full scale)−0.98−0.42−0.16−0.46 to 0.1454
  WISC-R verbal IQ−0.98−0.58−0.11−0.34 to 0.1139
  WISC-R performance IQ−0.98−0.55−0.13−0.44 to 0.1943
  Mathematical abilities (WRAT-R M)−0.98−0.58−0.11−0.37 to 0.1439
  Academic abilities (WJ)−0.98−0.79−0.09−0.24 to 0.1320
  • Total effect = the association between ELBW status and income attainment, while adjusting for covariates; direct effect = the association between ELBW status and income attainment, while adjusting for covariates and cognitive mediator; indirect effect = mediated effect. WJ, Woodcock–Johnson Psychoeducational Battery.

  • a % mediated = ab/c × 100.

  • * Significant indirect effect at the α = .05 level.