Census rate as a pragmatic indicator of emergency department crowding: a multicentre prospective observational...

Emergency department (ED) crowding affects patient flow, care timeliness, staff well-being, and frontline workload. Although several crowding metrics are available, their interpretability across EDs of different sizes remains uncertain. We compared Census Rate (CR) and the Community Emergency Department Overcrowding Scale (CEDOCS) against frontline-perceived workload across three French EDs.

We conducted a multicentre prospective observational study from 15 to 28 May 2023 in one university hospital and two community hospitals. Twice daily, operational variables were recorded and eligible frontline staff completed a 6-point staff workload assessment (SWA). The primary outcome was the association between SWA and each crowding metric. Spearman's rank correlation was prespecified as the primary analysis, with Pearson correlations and linear regression as sensitivity analyses. Overlapping dependent correlations were compared using Williams' test. Additional exploratory analyses examined empirical CR tertiles.

Eighty-four site-time observations were expected, of which 81 had complete data for the main analyses. CR showed a strong association with SWA (Spearman's ρ = 0.744, 95% CI 0.619 to 0.832; p < 0.001), whereas the association for CEDOCS was more moderate (ρ = 0.471, 95% CI 0.289 to 0.616; p < 0.001). The association between CR and SWA was significantly stronger than that between CEDOCS and SWA (difference in correlations 0.273, 95% CI 0.116 to 0.438; Williams' t = 4.728, df = 78; p < 0.001). In community hospitals, both metrics performed similarly, whereas CR showed a clearer advantage overall. Empirical CR tertiles were significantly associated with SWA and were used for exploratory interpretation within this dataset.

Across EDs of different sizes, CR showed a stronger association with frontline-perceived workload than CEDOCS. These findings suggest the potential value of CR as a simple and interpretable crowding metric to support shared situational awareness and workload-informed discussions, pending validation in broader settings and nurse-specific studies.