See how a running total differs from a rate of change using parcel deliveries:...

https://tango-wiki.win/index.php/When_Should_I_Use_a_Step_Graph_Instead_of_a_Line_Graph%3F

See how a running total differs from a rate of change using parcel deliveries: 120 parcels by noon is a total, while 15 parcels per hour describes a pace. The article shows how units and time windows make dashboard numbers easier to interpret.