Using research to examine a parenting plan
The practical factors research says matter and the boundary between a useful research principle and an individual court decision.
What should research contribute to a parenting‑plan argument?
Research can identify relevant questions and recurring risk factors. It cannot choose an arrangement without evidence about the individual child and family. The most defensible approach examines safety, established care, each relationship, developmental needs, conflict, transitions, distance, routines, and each parent's capacity.
Start with these papers
These are the main papers supporting the answer above. Open a research record for the findings, limitations, full citation, and original publication.
Using child development research to make appropriate custody and access decisions for young children
Start here for the original developmental guidance on frequent contact, two consecutive overnights for most two-year-olds, and longer separations as children mature.
Social science and parenting plans for young children: A consensus report
Read why shared parenting and overnights should not be prohibited solely because a child is young, and why no single schedule applies to every family.
Parental separation and overnight care of young children, Part II: Putting theory into practice
Start with the practical framework and the factors it says should be examined.
When this guide is useful
Use this guide when a party relies on a single study, an age chart, an attachment label, or a percentage as though it decides the case.
The boundary to keep
Population research provides context. Facts about the individual child and family determine whether a general pattern is relevant. Safety evidence can outweigh average findings from ordinary families.
Findings worth knowing
Development should shape the plan, not erase a parent
Kelly and Lamb argued for schedules that preserve meaningful relationships with both parents while matching the child's developmental capacity and established care.
Kelly and Lamb, 2000: read the evidence recordAttachment and parental involvement can be protected together
Pruett, McIntosh, and Kelly rejected a general prohibition on overnights while retaining conditional caution for conflict, unfamiliar care, and demanding arrangements.
Pruett, McIntosh, and Kelly, 2014: read the evidence recordThe practice framework identifies the facts that need evidence
The companion paper organised decisions around the child, relationships, parenting capacity, safety, conflict, caregiving history, and transitions.
McIntosh, Pruett, and Kelly, 2014: read the evidence recordAttachment science supplies principles, not an exact schedule
International consensus supports familiar safe caregivers, continuity of adequate care, and attachment networks while warning against individual overreach.
Forslund and colleagues, 2022: read the evidence recordEqual care can use shorter rotations
Two different questions are often confused. The first is how much care each parent should provide over time. The second is how many consecutive nights a child should spend away from either parent. A 50/50 plan can use short, frequent periods instead of requiring a young child to spend an entire week away from one parent.
What Kelly and Lamb actually recommended
Kelly and Lamb recommended contact with both parents every day or every other day for children younger than two or three when both relationships were established and the care was adequate. They considered most two-year-olds capable of two consecutive overnights with either parent. They advised against five-to-seven-day separations for toddlers. By approximately seven or eight, most children could usually manage five-to-seven-day separations. These were developmental recommendations drawn from wider research. They were not results from a trial comparing custody schedules.
Kelly and Lamb, 2000: read the evidence recordWhat one consecutive night for each year of age means
This refers to the maximum number of consecutive nights away from either parent. It does not mean one overnight during the entire year. As a rough example, a one-year-old would have blocks of no more than one overnight, while a two-year-old would have blocks of no more than two consecutive overnights. The exact formula has not been validated as a scientific rule and should not be presented to a court as a proven cutoff. However, the research does support the principle behind it. Younger children generally need shorter separations from both parents, and longer blocks become more manageable as children develop.
Equal care can use very short rotations
Where both parents already provide safe and familiar care, alternating days or single overnights can divide care without a long absence from either parent.
Two-night blocks reflect the clearest published example
Kelly and Lamb considered most two-year-olds able to manage two consecutive overnights. Equal care can be built across a repeating cycle without using seven-night blocks.
Longer blocks may be introduced gradually
Schedules such as 2-2-3 or other short repeating rotations may preserve frequent contact. The child's response, established care, routines, travel and the quality of transitions remain important.
Week-about care may become easier to manage
Kelly and Lamb considered most children at this stage better able to manage five-to-seven-day separations. School, activities, temperament and the child's own experience still matter.
The strongest objection and the evidence in response
General research cannot account for the particular child's temperament, distress, school, distance, parental conflict, violence, or caregiving history.
That is why a sound research argument should connect each general claim to evidence about the actual family. The research is most useful when it identifies what needs to be examined, tests an unsupported universal claim, or shows that a proposed risk is conditional rather than inevitable.
Open these papers next
Each link opens a plain-language record with the report summary, researchers’ conclusions, limitations, full citation, and original publication link.
Using child development research to make appropriate custody and access decisions for young children
Start here for the original developmental guidance on frequent contact, two consecutive overnights for most two-year-olds, and longer separations as children mature.
Joan B. Kelly & Michael E. Lamb (2000)Social science and parenting plans for young children: A consensus report
Read why shared parenting and overnights should not be prohibited solely because a child is young, and why no single schedule applies to every family.
Richard A. Warshak, with endorsers listed in the article (2014)Parental separation and overnight care of young children, Part II: Putting theory into practice
Start with the practical framework and the factors it says should be examined.
Jennifer E. McIntosh, Marsha Kline Pruett & Joan B. Kelly (2014)Parental separation and overnight care of young children, Part I: Consensus through theoretical and empirical integration
Read the research reasoning behind the practical framework.
Marsha Kline Pruett, Jennifer E. McIntosh & Joan B. Kelly (2014)Attachment goes to court: Child protection and custody issues
Read the current boundary between attachment principles and court decisions.
Forslund, Granqvist, van IJzendoorn, Sagi-Schwartz, Glaser, Steele, Hammarlund et al. (2022)Children’s and parents’ well-being in joint physical custody: A literature review
Read how international outcome evidence changes across family and national contexts.
Anja Steinbach (2019)