When Allegations Become Evidence: Confirmation Bias in High-Conflict Custody Evaluations
How assumptions, selective interpretation, and inadequate hypothesis testing can compromise forensic conclusions.
An allegation enters family court as a claim requiring examination. Yet somewhere between the initial referral, collateral interviews, psychological testing, and final report, an allegation may begin to acquire the appearance of an established fact.
The transformation is not necessarily intentional. It may occur through a series of seemingly reasonable decisions: which witnesses are interviewed, which records receive attention, how ambiguous behavior is interpreted, and which explanations are ultimately considered credible.
The danger is not simply that an evaluator might reach an incorrect conclusion.
It is that the evaluation process itself may become organized around confirming a conclusion that has not yet been established.
In cases involving child contact refusal, allegations of parental alienation, sexual abuse, or psychological maltreatment, the consequences of such errors can be substantial.
Confirmation Bias: A Methodological Concern, Not Merely a Personal Flaw
Confirmation bias refers to the tendency to seek, interpret, or favor information consistent with existing beliefs or expectations.
In a 2026 article published in the Journal of Legal Medicine, Resnick and VanDercar examine confirmation bias in forensic mental health assessments, including the influence of anchoring, adversarial pressures, and observer expectations on professional judgment.
Importantly, the concern is not limited to evaluators who consciously favor one party. Cognitive biases can influence how professionals process information even when they intend to remain objective.
The American Psychological Association's Specialty Guidelines for Forensic Psychology (2013) address this problem through an emphasis on impartiality, appropriate methodology, and examination of plausible rival hypotheses.
Guideline 9.01 specifically emphasizes examining forensic questions from reasonable alternative perspectives and obtaining information capable of differentiating competing explanations.
This is a critical distinction.
Collecting information consistent with a hypothesis is not the same as adequately testing that hypothesis.
When Child Contact Refusal Becomes Presumed Alienation
Consider a child who persistently refuses contact with one parent.
The referring attorney may describe the situation as parental alienation. The rejected parent may report that the other parent is interfering with the relationship. The favored parent may insist the child's refusal reflects genuine fear or prior harmful experiences.
Each account offers a possible explanation. None, standing alone, establishes the cause of the child's behavior.
A methodologically sound evaluation must consider relevant competing explanations, which may include:
Exposure to denigrating or relationship-undermining behavior.
Prior experiences of harsh, frightening, neglectful, or abusive parenting.
Developmental factors and the child's individual vulnerabilities.
Loyalty conflicts and the effects of prolonged interparental conflict.
Changes in attachment, family relationships, and parent-child interactions.
Multiple interacting factors rather than a single cause.
These explanations are not mutually exclusive.
An evaluator who begins with the assumption that the child's refusal is primarily the product of parental manipulation risks interpreting subsequent information through that framework.
Conversely, an evaluator who assumes that every refusal reflects justified estrangement may overlook meaningful evidence of coercive influence or relationship interference.
Neither approach satisfies the need for balanced hypothesis testing.
The relevant forensic question is not which parent's explanation is more compelling at the outset.
It is which explanation, or combination of explanations, is best supported by the available evidence.
Sexual Abuse Allegations: Where Methodological Precision Becomes Essential
Allegations of child sexual abuse introduce additional complexity.
The seriousness of an allegation demands appropriate attention to child safety, investigative integrity, and the potential consequences of both false-positive and false-negative conclusions.
Research on forensic interviewing demonstrates that interview procedures matter.
Benia and colleagues (2015), in a meta-analysis of the National Institute of Child Health and Human Development investigative interview protocol, found that protocol-based interviews generally involved more open invitations and fewer suggestive prompts than comparison interviews. The study also identified limitations, including differences in findings involving preschool-aged children.
O'Donohue and Cirlugea (2021) specifically examined confirmation bias in child sexual abuse forensic interviews, discussing how prior assumptions and investigative context may affect the questioning process.
These findings have practical implications.
An evaluator reviewing a sexual abuse allegation should consider the circumstances of disclosure, the available interview documentation, the nature of prior questioning, relevant collateral information, and the limits of the evaluator's own professional role.
However, methodological concerns about an interview do not independently establish that an allegation is false.
Similarly, the absence of physical findings or independent corroboration does not establish that abuse did not occur.
An allegation may remain unsubstantiated without being disproven. An account may warrant further investigation without having been established as fact.
These distinctions are essential to scientifically responsible forensic communication.
The Problem of Selective Corroboration
One of the more subtle manifestations of confirmation bias occurs when an evaluator obtains information from multiple sources but does not evaluate those sources with comparable scrutiny.
A report may include numerous collateral interviews, extensive records, and standardized psychological measures.
The sheer volume of information may create an impression of methodological rigor.
Yet quantity does not necessarily establish evidentiary quality.
Consider whether the evaluator:
Examined evidence inconsistent with the leading hypothesis.
Distinguished independent corroboration from repeated accounts originating from the same source.
Evaluated the reliability, relevance, and limitations of collateral information.
Considered whether psychological testing actually supports the specific forensic inference being made.
Explained significant contradictory evidence rather than omitting or minimizing it.
APA Guideline 9.02 emphasizes the use of multiple information sources and corroboration of important data when feasible. Where information remains uncorroborated, the guidelines encourage practitioners to identify that limitation.
Likewise, Guideline 11.02 emphasizes distinguishing observations, inferences, and conclusions.
These are not merely documentation preferences.
They are central to determining whether the reader can trace an expert's reasoning from the underlying evidence to the ultimate opinion.
What Attorneys Should Examine
For attorneys evaluating a forensic report, the central question should extend beyond whether the expert's conclusion favors or disadvantages their client.
Instead, counsel should examine the reasoning process.
Five questions are particularly useful:
What hypotheses were considered? Did the evaluator examine reasonable alternative explanations, or did the initial referral narrative become the dominant explanatory framework?
What evidence could have changed the evaluator's opinion? A conclusion that appears insulated from contradictory evidence warrants closer examination of its methodological foundation.
Were collateral sources evaluated critically? Multiple witnesses repeating information from a common source should not automatically be treated as independent corroboration.
Were the limits of psychological assessment respected? Did the evaluator explain how the chosen methods support the particular opinions offered, without extending test findings beyond their established utility?
Can the conclusions be traced to the evidence? Does the report clearly distinguish documented facts, reported allegations, clinical observations, professional inferences, and ultimate opinions?
These questions do not presume that an expert is biased or that an unfavorable opinion is unreliable.
They provide a framework for examining whether the evaluation process supports the weight assigned to its conclusions.
Objectivity Is Demonstrated Through Methodology
The Association of Family and Conciliation Courts' Guidelines for Parenting Plan Evaluations in Family Law Cases (2022) provide an additional professional framework for approaching complex custody evaluations.
Alongside the APA forensic guidelines, they reinforce the importance of careful evaluative practice in matters involving consequential family decisions.
Forensic objectivity should not be understood simply as an evaluator's declaration of neutrality.
It must be reflected in the procedures employed, the evidence considered, the limitations acknowledged, and the transparency of the reasoning presented.
This is especially important when the allegations involve child sexual abuse or persistent child contact refusal—circumstances in which premature conclusions can carry significant consequences for children and families.
A defensible forensic opinion need not eliminate every uncertainty.
It must, however, distinguish what is known from what is inferred, acknowledge what remains unresolved, and demonstrate that reasonable competing explanations received appropriate consideration.
The purpose of a forensic evaluation is not to find evidence that supports the allegation. It is to determine what the evidence can—and cannot—reasonably support.
Upright Forensic Solutions, LLC
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References
American Psychological Association. (2013). Specialty guidelines for forensic psychology. American Psychologist, 68(1), 7–19. https://doi.org/10.1037/a0029889
Association of Family and Conciliation Courts. (2022). Guidelines for parenting plan evaluations in family law cases. https://www.afccnet.org/Resource-Center/Practice-Guidelines
Benia, L. R., Hauck-Filho, N., Dillenburg, M., & Stein, L. M. (2015). The NICHD investigative interview protocol: A meta-analytic review. Journal of Child Sexual Abuse, 24(3), 259–279. https://doi.org/10.1080/10538712.2015.1006749
O'Donohue, W., & Cirlugea, O. (2021). Controlling for confirmation bias in child sexual abuse interviews. Journal of the American Academy of Psychiatry and the Law. https://doi.org/10.29158/JAAPL.200109-20
Resnick, P. J., & VanDercar, A. H. (2026). Confirmation bias: An enemy of objectivity in forensic mental health assessments. Journal of Legal Medicine. Advance online publication. https://doi.org/10.1080/01947648.2026.2730937
