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SynthesisDevelopmental research review2000

Using child development research to make appropriate custody and access decisions for young children

Joan B. Kelly & Michael E. Lamb

Family and Conciliation Courts Review

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Report summary

How should knowledge about attachment, parental involvement, and young children’s development inform parenting plans after separation?

The review recommended frequent contact with both parents for young children when both relationships were established and care was adequate. For children younger than two or three, the authors preferred contact every day or every other day. They considered most two-year-olds capable of two consecutive overnights with either parent, while advising against five-to-seven-day separations for toddlers. By approximately seven or eight, most children could usually manage five-to-seven-day separations.

Across later work, rigid age cut-offs have given way to more conditional frameworks based on established care, safety, conflict, transitions, and child characteristics.

Authors' interpretation

Researchers' conclusions

The authors supported preserving meaningful relationships with both parents through schedules matched to the child's developmental capacity. Their examples show that equal care and the length of each residential block are separate questions. They did not propose a strict rule limiting consecutive nights away from either parent to one night for each year of the child's age, or one schedule for every child.

This is a plain-language summary of the researchers' conclusion. It is not advice for an individual family.

Study at a glance

How the report was produced

Research designDevelopmental research review
SampleNarrative integration of developmental literature
PopulationInfants and young children
SettingUnited States

These papers integrate research rather than randomly assign families to plans. Their recommendations must be separated from the underlying empirical findings.

Careful interpretation

What this paper supports

Reasonably supports

  • Making assumptions, evidence, and value judgments visible when moving from research to guidance.
  • Individualizing plans around actual caregiving history and the child’s functioning.
  • Protecting both developmental security and meaningful parent-child relationships where possible.
  • Reviewing arrangements as children and family conditions change.

Does not establish

  • Presenting a professional framework as though it were a randomized trial.
  • Using an age chart without examining the facts that the framework says matter.
  • Treating either equal time or primary residence as scientifically mandatory in every ordinary case.
  • Allowing a population-level recommendation to displace safety evidence in an individual family.
Read with care

Important limitations

  • A research-to-practice review rather than a trial of particular custody schedules
  • The direct evidence on separated infants was limited at publication
  • The schedule examples were developmental recommendations rather than experimentally validated cutoffs
  • Policy application requires facts not supplied by population research
Optional deeper reading

Evidence context and debate

Open the sections below for the wider research context, points of agreement, and areas that remain contested.

Why this question matters

Developmental research entered family-law guidance through attempts to translate attachment, separation, caregiving, and parental-involvement findings into practical schedules.

Parenting-plan papers sit at the boundary between science and recommendation. They draw on attachment, parental involvement, separation, sleep, conflict, and developmental research, but the plan itself is not usually tested through random assignment. A reader must therefore distinguish the empirical findings being cited from the authors’ professional synthesis of what those findings imply.

Kelly and Lamb emphasized developmental capacities and maintaining both relationships. Warshak argued that blanket restrictions undervalued father-child relationships and were not supported by direct evidence. McIntosh, Pruett, and Kelly’s companion papers integrated attachment and involvement while providing a structured set of child, relationship, and coparenting considerations.

Across these papers, the field has moved away from a single primary-parent formula. The remaining disagreement is less about whether both relationships matter and more about the prudent starting point, the pace of transitions, and how to respond when the evidence on a particular age or schedule is sparse.

Where researchers agree and disagree
Where researchers agree

There is substantial agreement that plans should be individualized and should protect children from harmful conflict, abuse, neglect, and abrupt loss of familiar care.

Where views differ

Authors differ over the preferred default when evidence is incomplete and over how quickly substantial overnight care should develop for very young children.

Comparison with other research

Kelly & Lamb, 2000

Used developmental research to support schedules that preserve both relationships while reflecting the child’s capacities and established care.

Warshak, 2014

Opposed blanket overnight restrictions and argued for maximizing both relationships in ordinary circumstances, with individualized exceptions.

Pruett, McIntosh & Kelly, 2014 Part I

Joined attachment and involvement perspectives through a triadic secure-base model and retained conditional caution.

McIntosh, Pruett & Kelly, 2014 Part II

Translated the integration into a practice framework covering the child, relationships, parenting capacity, safety, conflict, and transition demands.

How the evidence developed later
  • The literature increasingly states exceptions and boundary conditions explicitly.

  • Triadic and network perspectives have replaced an either-or contest between attachment and involvement.

  • Recent consensus warns courts that attachment science supplies principles, not an automatic schedule.

  • Policy evaluation is developing as a separate evidence stream from developmental guidance.

Sources

Read the paper and related research

This report

Joan B. Kelly & Michael E. Lamb (2000). Using child development research to make appropriate custody and access decisions for young children. Family and Conciliation Courts Review, 38(3), 297–311. https://doi.org/10.1111/j.174-1617.2000.tb00577.x

Continue the evidence chain

Configurations of mother–child and father–child attachment relationships as predictors of child language competence

Next, see what happened when researchers combined information about children's secure relationships with both parents.

Dagan, Schuengel, Verhage, Madigan, Roisman et al. (2024). Configurations of mother–child and father–child attachment relationships as predictors of child language competence. Child Development, 95(1), 50–69. https://doi.org/10.1111/cdev.13998

Record checked against the linked scholarly source. Last editorial review: 22 July 2026, as part of a batch review of the current collection.