Architecting and designing : DoDAF : DoDAF 1.5 Activity Based Methodology (ABM) : Developing operational views with DoDAF ABM : ABM syntax rules : Activity outputs must be different from their inputs
  
Activity outputs must be different from their inputs
An Activity must have a different output than its input.
This means the following diagram is not valid:
The following example is valid:
See also
ABM syntax rules