In the U.S., it is a constitutionally guaranteed right, based on the First Amendment, that no one may be told by any authority where they have to live (freedom of association), absent certain types of criminal probation or parole orders. Thus, when a family court judge makes a decision regarding a move-away case, the only order the court can make is where the primary residence of the children will be – whether the children are to stay behind or move with the parent who is moving.
As one might imagine, most judges are no better at determining which one of two otherwise normal-seeming parents should prevail in these cases. So, in many cases, the judge will order that a custodial evaluation be conducted by a psychological professional. In most cases, these evaluators are Ph.D. psychologists, who conduct psychological testing of the parents, among other things. The psych tests are simply to rule out any pathology in either parent, and, in most cases, both parents fall into the “normal” range. However, sometimes the tests pick up pathology, usually in the form of personality disorders. It is rare for evaluations to find more severe types of psychological pathology, such as schizophrenia, psychosis, or severe bipolar disorder, since the symptoms of those conditions are usually clearly manifested, leading to hospitalization or run-ins with law enforcement, creating an existing diagnosis, that is usually considered by the court when parents first separate. Custody evaluations are paid for by the parents, if they can afford them. They either pay equally, or unequally in proportion to their respective incomes. Evaluations typically cost many thousands of dollars. Based on all the evidence examined, including interviews with the parents, children, and any collateral individuals, such as relatives or therapists, the evaluator makes a recommendation to the court. Evaluators are allowed much more access to evidence than the court, itself, and the reports are usually received into evidence without foundation, which would, otherwise require subpoenaing the evaluator as a witness to “authenticate” the report. Custody evaluators are required to have appropriate education and training per the Family Code.