OBJECTIVE: To examine the interrater reliability between nurse- and physical therapist (PT)-recorded scores from the Activity Measure for Post-Acute Care 6-Clicks Basic Mobility short form across hospitals, services, and categories of assessment timing. DESIGN: Cross-sectional study of retrospective electronic health record data. SETTING: Data were collected for patients in 11 hospitals between January 2020 and October 2022. Nurse- and PT-recorded 6-Clicks mobility scores were paired by date. PARTICIPANTS: There were 535,974 unique score pairs for 127,583 patients. INTERVENTIONS: Not applicable. MAIN OUTCOME: Interrater reliability was examined using intraclass correlation coefficients where values <
0.5, 0.5-0.75, 0.75-0.9, and >
0.9 indicate poor, moderate, good, and excellent reliability, respectively. In secondary analyses, score pairs were categorized according to: (1) hospital, (2) unit type (intensive care vs other), (3) clinical service, and (4) relative timing of nurse- and PT-recorded scores. MEASURES: 6-Clicks Basic Mobility short form. RESULTS: The interrater reliability was good overall, in 6 hospitals (moderate in 4 hospitals and poor in 1), in both intensive care and other units, for 4 out of 5 clinical services (moderate for 1), and for 4 out of 5 timing categories (moderate for 1). CONCLUSIONS: In this large study of real-world data, nurse- and PT-recorded 6-Clicks mobility scores had moderate-to-good interrater reliability.