Final answer:
The process improvement tool used in this situation is a Pareto chart, which helps identify the most significant causes of medication errors that need to be addressed for improvement.
Step-by-step explanation:
The process improvement tool that is used in this situation is the Pareto chart. A Pareto chart is a type of bar graph that displays data in descending order of magnitude, showing the most significant causes or factors contributing to a problem. In this case, the Pareto chart helps the hospital staff and administration identify the top four causes of medication errors that need to be focused on for improvement. By addressing these main causes, the hospital can effectively reduce medication errors.