Temporal and Subspecialty Variability in Radiologist Workload: A 2-Year Single-Center Retrospective Study.

RATIONALE AND OBJECTIVES: Radiology workload assessments are commonly based on aggregate volumes or Relative Value Unit (RVU) totals, which may obscure short-term temporal variability that contributes to perceived workload variability. This study characterizes intraday, intraweek, and longitudinal variability in radiologist workload across subspecialties using normalized workload metrics. MATERIALS AND METHODS: A retrospective analysis of 24 months of radiology reports was performed at a large academic medical center. More than 1.25 million reports across seven diagnostic radiology subspecialties were analyzed. Workload was quantified using work RVUs normalized by divisional clinical full-time equivalents (nwRVU). Temporal variability was assessed across time of day and day of week using coefficients of variation of the exam completion time. Longitudinal variability was evaluated using 4-week moving averages, a normalized volatility index, and median absolute deviation. Study addenda were analyzed as a secondary proxy for cognitive load. RESULTS: Substantial temporal variability was observed across all divisions, with day-of-week variability exceeding intraday variability in most subspecialties. Pediatric and CardioThoracic divisions demonstrated the highest variability, while Neuro and Emergency showed comparatively stable weekday patterns despite high absolute workload. Start-of-day hours were associated with increased report finalization variability across divisions, while examination completions remained stable through the morning in weekday divisions. Longitudinal analysis revealed seasonal trends and substantial week-to-week fluctuations, with volatility not consistently aligned with total workload magnitude. Divisions with similar nwRVU volumes exhibited distinct variability signatures. CONCLUSION: Radiology workload predictability varies substantially by subspecialty and timing, independent of total volume. Temporal variability occurs on intraday, intraweek, and seasonal time scales and is not captured by traditional workload summaries. Incorporating temporal variability metrics may help inform staffing and operational planning strategies.