Add Health Study: Adopted/Foster Care and Divorce Risk

Study Description

The Add Health study, officially the National Longitudinal Study of Adolescent to Adult Health, is a landmark U.S. project tracking how early-life experiences like adoption or foster care affect adult outcomes, including divorce. Launched in 1994, it shows that adopted or foster children have a 70% higher divorce risk due to instability, attachment disruptions, and trauma.

Research Findings

For example, foster kids often experience multiple placements, leading to emotional scars that manifest in adult relationships as trust issues or conflict avoidance. The effect is stronger if combined with parental divorce (RR 2.0+), as adoption/foster frequently overlaps with family breakdown. Protective (no adoption/foster): RR 0.9 (–10%). This work informs child welfare policies, emphasizing stable placements to reduce long-term risks. The study's long-term tracking reveals that these childhood experiences have enduring impacts, influencing partner choice, marital satisfaction, and even parenting styles in adulthood. Add Health has been instrumental in shifting focus from just divorce to broader family instability, highlighting how foster care's transient nature can mimic divorce's effects. With over 20,000 participants followed for decades, it's a gold standard for understanding how early adversity shapes family life cycles.

Experimental Setup

Add Health is a cohort study starting with over 20,000 adolescents in 1994–1995, followed through four waves into adulthood (latest 2016–2018). Participants reported family structure, including adoption or foster care, and adult outcomes like marriage and divorce. Researchers used logistic regression and survival models to analyze divorce probability over 10–20 years, controlling for parental divorce, SES, race, education, and mental health. High-risk groups (adopted/foster) were compared to controls, with statistical tests for interactions (e.g., with divorce).

Drawbacks/Limitations on Finding

Retrospective reports in early waves risk bias, and high attrition (30–40% loss over time) may skew results toward stable participants. The U.S. focus limits global applicability, and causality is correlational—adoption/foster might proxy for unmeasured genetics or poverty. Shortcomings in mental health measures (self-report) underplay overlaps. Despite this, the large, longitudinal sample makes findings highly credible.

Calculator Integration

At Odds on Life, Add Health data sets the adopted/foster logit at +0.262 (yes) and -0.095 (no); halved if parental divorce for overlap. This is part of the family instability sub-score, capped at 0.94 to balance overlaps while honoring the study's RR 1.7.

Study References

• National Longitudinal Study of Adolescent to Adult Health (Add Health)
  Add Health Main Page – University of North Carolina at Chapel Hill
  Adopted/foster care: +70% divorce risk

Related Factors

This study directly informs the calculator's assessment of:

• Adopted or Foster Care Status – Primary factor showing 70% increased divorce risk for individuals who experienced adoption or foster care
• Parental Divorce – Related factor that amplifies adoption/foster effects, with combined risk reaching RR 2.0+
• Parental Conflict – Part of the broader family instability context that interacts with adoption/foster status

These factors are combined in a family instability sub-score (capped at 0.94) to prevent double-counting overlapping risks. The study's finding that foster care's transient nature can mimic divorce's effects aligns with research showing that broader family instability, not just divorce, impacts offspring marital stability. The Add Health study's long-term tracking has been crucial in understanding how early-life adversity shapes adult relationship outcomes.