Family Parameters Sample n=1,200,000

Adjust birth rank, sibship size, and parental resource dilution parameters based on longitudinal register data reported by The Washington Post.
1st 4th+
0.4x 1.2x
Simulates early childhood reading time, financial support & parental undivided attention.
Research Cohort Presets

Comparative Lifetime Trajectory Second-Born Deficit

Earnings Differential
-8.4%
vs Firstborn cohort at age 35
Education Attainment Gap
-0.6 yrs
Mean difference in schooling
Mental Health Risk Ratio
1.14x
Adolescent outpatient incidence

Sibship Trajectory Curves (Age 0 - 40)

Danish National Register Cohorts
1st Born Baseline
Selected Position Trajectory
Parental Investment Horizon
Primary Driver
Resource dilution and parental attention shift during critical early developmental windows create enduring cumulative differentials in human capital accumulation.
Methodology & Evidence: Synthesized from peer-reviewed analyses of 1.2 million individuals in the Danish Civil Registration System, detailing sibling economic disparity, maternal age controls, and sibling fixed effects reported in The Washington Post (2024). Values model within-family variance across standardized lifetime markers.
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