TOPIC: Mandatory vs. Internal dependencies

Hello,

Can someone please explain to me why the following example from the PMBOK Guide is NOT a Discretionary dependency?

PMBOK 5th, Page: 158:

For example, if the team cannot test a machine until they assemble it, this is an internal mandatory dependency. The project management team determines which dependencies are internal during the process of sequencing the activities.

Why isn't it both?

Mandatory and Internal dependency
"Mandatory dependencies are those that are legally or contractually required or inherent in the nature of the work."

Thanks in advance for your help.

Regards,
Marc

Physical limitation is a mandatory dependency. I'm trying to clarify when a physical dependency is mandatory and also internal, which one do we choose

Hi Rae,

I am not sure I understand your question correctly.
A dependence cannot be mandatory and discretionary at the same time; similarly, external and internal are mutually exclusive attributes. However, mandatory and internal are not mutually exclusive, so I don't see why to choose between the two.
Also, keep in mind that some dependencies may not fall in one of the two categories per se, but depending on the context. A dependency is not something "absolute", but it expresses a logical relationship between two activities. Do you have a specific example in mind?

Gabriella