Difference between activities and tasks in a BPMN context

[Siva Narayana]

Hi,

I am new to BPMN and trying to get understand the difference between
the terms 'Activitiy' and 'Task' in a BPMN context. Would it be ok to
do define them as:
‘Activity’ is defined as an event that occurs during the detailed
design phase of the project.

‘Task’ is defined is an actionable item that needs to be performed to
complete an activity. An activity may consist of one or more tasks.

Thank you for your comments and feedback.

Best Regards
Siva

[MPA]

Hi Siva,

"Activity" is the term under which 'Tasks' and 'Sub-Processes' are
united, much as "Events" is the term under which 'Start',
'Intermediate', and 'End' are united. So all tasks and sub-processes
are "activities", whereas there is obviously a distinct difference
between a task and a sub-process. :)

I hope I could help you a little.

Have a good weekend

Malte Philipp

[Neal McWhorter]

Just to further clarify the muddy picture in the standard

A Process is a top-level activity which is instantiable and is not contained within any other activity.

A Task is an atomic activity and therefore must not contain other activities or other process elements.

Any other activity is a sub-process.

Neal

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[Siva Narayana Reddy Koppula]

Hi Malte/Neal,

 

Thank you for your kind response. In a way I find the use of these words (Activity and Task) bit confusing in the BPMN context. According to BPMN 2.0, it appears Activitives consists of Tasks. Tasks in turn can contain sub process. Sub process in BMPN again defined as an Activity that can be refined... (in the BPM2.0 poster)

 

Actually, I read somwhere in BPI material that we can show process maps either at 'Activity' level or at 'Task' level - task level being 'more detailed' than activity level and I am struggling to find the clear difference between them. But from BPMN perspective, it appears Activities are more of an abstract class to use software analogy. Would you agree?

 

Thank you for your comments!

 

Best Regards

Siva

[Neal McWhorter]

Siva,

You're right to think of Activity as an abstract class. In fact the standard says that:

"The Activity class is an abstract element, sub-classing from FlowElement"

So to summarize...

Activity is the supertype for Task and Subprocess.

Process is the outermost container for all FlowElements and no process can contain another process.

A subprocess is any collection of of flow elements contained within an Activity.

A task contains no other flow elements.

To add confusion there is also an "Abstract Task" which is a Task which isn't one of the defined types of Task (e.g. Service Task, Send Task, Receive Task, etc.). These variations of Tasks are actually subtypes of Abstract Task and  Abstract Task is itself a subtype of Activity. 

The terminology does make sense once you get used to it but it is confusing initially.

Hope that helps...

	Experience + Leadership
Neal McWhorter | Connect with me on Linkedin President Business Architecture Guild Board Member neal.mc...@strategicvaluepartners.com www.StrategicValuePartners.com	Strategic Value Partners Chicago, Illinois Tel:   773-819-0018