Frequency distribution of antecedent (occurrence) events
This bar graph of event code categories shows where the antecedent events occurred for a particular type of consequent event.

For example, this is a distribution of the antededent events for Order Entry consequent events with a high risk index. As you can see, the greatest number of antededents occurred in sample collection.
The frequency distribution of antecedents will show where in the process the failures were occurring for that particular type of consequent event. These peaks should be examined closely because they give an indication of where process improvements can be made.