Arrow diagramming method (ADM) is a network diagramming technique in which activities are represented by arrows. ADM is also known as the activity-on-arrow (AOA) method. Arrow diagramming method (ADM) is a network diagramming technique in which activities are represented by arrows. ADM is also known as the activity-on-arrow (AOA) method. ADM is used for scheduling activities in a project plan. Precedence relationships between activities are represented by circles connected by one or more arrows. The length of the arrow represents the duration of the relevant activity. ADM only shows finish-to-start relationships, meaning that each activity is completed before the successor activity starts.