Methods SAS version 9.2 (Carey, NC) was used to create two groups of visualizations: (1) a separate heatmap for each hospital, showing how each individual ED performs on each of 13 data quality measures and (2) a separate heatmap for each data quality measure, showing how data quality varies by ED. The heatmaps summarize data by month and year, though other visualizations (e.g., daily or weekly) are also possible. For each row on the heatmap, a color change indicates that data quality has shifted over time. Blocks with stable color over time suggests that there has not been a change in data quality. White space on the heatmap highlights periods of time where data were not recorded by the system and can provide a visual cue for newly added EDs, hospital closures or data drop-offs. The heatmaps are generated monthly for each of 13 data quality measures. SAS code for generating the heatmaps will be provided at the session.