There is increasing pressure to effectively treat patients with complex care needs from the moment of admission to the general hospital. In this study, the authors developed a measurement strategy for hospital-based care complexity. The authors' four-factor model describes the interrelations between complexity indicators, highlighting differences between length of stay (LOS), objective complexity (such as medications or consultations), complexity ratings by the nurse, and complexity ratings by the doctor. Their findings illustrate limitations in the use of LOS as a sole indicator for care complexity. The authors show how objective and subjective complexity indicators can be used for early and valid detection of patients needing interdisciplinary care.