AbstractThis article presents research performed to identify those patient classification variables that are most relevant for differentiating various patient categories. The nursing care time needed by patients in different categories was measured by judgment of head nurses. The data for this research were collected over a period of 2 weeks during day and afternoon shifts on a busy surgical ward in a 300‐bed suburban acute‐care general hospital. The data included an extensive list of auditable patient status items, as well as head nurse judgments. Statistical analysis of the data indicated that only a fe patient classification variables are necessary to be included in classification instruments. The study also revealed that different sets of classification variables are essential for different nursing shifts on the same unit.