Custody data as decision-theory information: Evaluating a psychological contribution by its value to a decision maker

Many issues raised by O'Donohue and Bradley (this issue) are epistemologic in nature, challenging what we can understand and predict in the child cust ody area, both currently and in the future. Our commentary presents a four- tiered model that can be used to assess the degree to which a contribution to the field can be considered scientific. Proof is offered that data exist which conform to this model. The advantages of seeing psychology as a deci sion science are given. The main criteria of a decision science are detaile d, along with the implications of these criteria for custody-relevant resea rch. Validity studies are considered from the perspective of "value to a de cision maker" (with an emphasis on relevance) rather than from the sole per spective of the point in time when such studies are conducted. Several area s often confused by commentators in the custody field are specified. These include confusing reliability and validity issues with the issue of the env ironments in which the predictions of a model are applicable, the misguided assumption that a concept cannot be validated and useful until its definit ion finds universal acceptance, and the important implications for validity studies in separating methods for recommending a legal custodian from thos e used to suggest a time-share plan. Next, the role of values in all scienc es is considered, and the (negative) implications in assuming that values c an be separated from so-called "facts." Finally, the recommendation for a m oratorium on practice advocated by O'Donohue and Bradley is considered from epistemological, ethical, and practical perspectives.