A custody evaluation is when an objective third party is paid to assess each of the parents in order to assist the court in making a determination as to custody.  Either party may ask the court to have a custody evaluation performed.  As a matter of logistics, it is preferable to have a custody evaluation requested early on in the legal process so as not to cause unnecessary delay.  Custody evaluations may take anywhere from a week to a month, depending on how in-depth the evaluation is.  In addition, the evaluation may involve interviews with the parties as well as collateral witnesses and psychological testing of both parents and the children.