The aim of this study was twofold-(1) to compare the current ED staffing workload alert system to clinicians' perceptions of workload in the ED, and (2) to examine the potential impact of a multi-faceted, systems-level intervention on clinicians' perceptions of workload. Constant flow of patients into the Emergency Departments (ED) regularly increases the workload of clinicians and can compromise the quality of care delivery and patient safety. An automatic staffing workload alert system was created and implemented in response to an observed shift in patient volume to the overnight hours at one academic quaternary care center. Surveys addressing workload and interruptions were administered to ED clinicians, pre- and post-intervention implementation. Output from the staffing workload alert system was recorded for each clinician shift. Clinicians' perceptions of workload were able to predict swing shift activations, X2(6) = 14.14, p = 0.028. Only the performance subscale significantly correlated with swing shift activations, p=0.006. A Kruskal-Wallis H test found perceived interruptions changed following systems- level changes, x2(l) = 7.195, p ~ 0.007. Utilizing subjective measure of clinicians' workload validated an objective, automated staffing workload alert system that determined if swing shift activations are necessary.