The director may provide facilities and personnel for a diagnostic intake and classification center. The work of the center shall include a scientific study of each inmate, the inmate’s career and life history, the causes of the inmate’s criminal acts and recommendations for the inmate’s custody, care, training, employment, and counseling with a view to rehabilitation and to the protection of society. To facilitate the work of the center and to aid in the rehabilitation of the inmates, the trial judge, prosecuting attorney, and presentence investigators shall furnish the director with any previously authorized presentence investigation report and a full statement of facts and circumstances attending the commission of the offense so far as known or believed by them. If the department develops and utilizes an inmate classification system, it must, within a reasonable time, present evidence from independent experts as to the effectiveness and validity of the classification system.