What is the purpose of annotations in a run chart?

Annotations in a run chart serve a critical purpose in enhancing the understanding of the data presented. Specifically, they are used to show how specific changes or interventions have influenced the pattern of the data over time. By marking points on the chart that correlate with actions taken or changes implemented, viewers can directly relate those changes to observed shifts in the data trends. This helps in identifying whether certain actions led to improvements or declines, thereby allowing for deeper analysis of cause-and-effect relationships.

While labeling the median, clarifying data points, and indicating importance of the data are all valuable in data presentation, none of these aspects have the same direct relevance to the actions or changes being analyzed as annotations do. Annotations clearly establish a timeline and context for viewers, making it easier to draw insights about the effectiveness of improvements in a QI initiative.