To understand the problems associated with large-scale change in mental hospitals, the assessment of organizational factors is of primary importance. The unitization of Philadelphia State Hospital provided the setting for discussing one approach to this assessment. Through the use of questionnaires, participant observation, and interviewing, the authors conclude that the more segmented the hospital, the lower the potential for organization-wide change. They discuss some implications for patient care and for actions to be taken by hospital administrators contemplating major changes.Abstract Teaser