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SysML V1.4 Actor vs Stakeholder

PostPosted: Thu Mar 01, 2018 3:44 pm
by theokahn
Hello- I'm trying to better understand when/how to use the new (V1.4) Stakeholder element. How does it compare/contrast with Actor?

It appears that <<Stakeholder>> was added to support the new (V1.4) Viewpoint/View semantics. The definitions (from OMG specs) for the two elements are:

SysML 1.4
A stakeholder represents a role, group, or individual who has concerns that will be addressed by the View of the model.

UML 2.51
An Actor specifies a role played by a user or any other system that interacts with the subject.

I could not find an Actor definition in the SysML V1.4 spec and so assume it is applied as is from the UML spec.

So, what is the relationship between them? I've not been able to find any documentation addressing that issue. We might say that an Actor is a type-of Stakeholder in-so-far as all Actors have to interact with the system and so have concerns. But, do all Actors have "concerns that will be addressed by the View of the model?" Is that a difference? Also, can the word "role" in the Stakeholder definition refer to a system? It clearly does for Actors. That is, can systems be Stakeholders?

I'm really temped to just use Stakeholder and deprecate Actor. I think using both Actor and Stakeholder in the same model is confusing. But, Stakeholder is not an approved node in the Use Case Diagram (See V1.4 spec). However, MD does not throw a validation error and Sandy Friedenthal uses Stakeholders in his recent (uses V1.4) model. See:

I have to assume that the spec developers have a rationale for including both stereotypes and that there are important differences between them.

Can anyone shed some light on this?

Thank you, -Ted Kahn