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Functionality vs Functon

Is a Function the Same a Functionality?

I was recently asked by Jan van Bon from the Netherlands to define “the difference between a Function and Functonality”.

My reply was,

“A Business Function (or Function) is a core activity of an enterprise. It is something that the enterprise must do in order to meet its objectives and continue in existence.

Examples, of functions would be, ‘Sell Product to Customer’, ‘Bill Customer for Products Delivered’, ‘Recruit Employee’, etc.

‘Functionality’ is a general English phrase that is generally used when referring to a computerised system in defining what Business Functions the system fully or partly supports.”

Jan then came back with the following additional questions:

“You say a Business Function is a set of activities. Then let me ask you the next question:

  • does a function include people and knowledge?
  • does a function include products?
  • does a function include all of these?
  • is a function a result?”

Let me address these questions one at a time.

Does a Function Include People?

A Function does not include people. It may be performed by people but, alternatively, it could be fully automated and require no human input.

Does a Function Include Knowledge?

Well this depends on your definition of ‘knowledge’. All Functions require information (data in a context) as an input and may transform this information or create new information. As such, every Function will have an information output.

Every function will contain function logic and may also include business rules. In fully automated Functions, these will be built into the module executing the Function. Is this knowledge? Well perhaps it is as, without having the logic and business rules built into an automated module, humans with that knowledge would be required to perform the Function.

Does a Function Include Products?

A Function will always result in a product either physical or abstract. For example:

Function Product Product Type
Manufacture Autoparts Manufactured autoparts. Physical
Recruit Employee Recruited Employee. Abstract
Calculate Tax Calculated tax on item. Abstract

Does a Function Include All of These?

As the answers above show, sometimes ‘yes’ and sometimes ‘no’.

Is a Function a Result?

No a Function is not a result.

A Function is an activity that brings about a result. That result will be the delivery of the product for the Function, together with all of the information necessary to be able to ascertain that the Function has been successfully completed or, if not successfully completed, rolled back to the starting state.

Note: Function is synonymous with Business Function.

Read more on Business Function Modelling


10 Responses to “Functionality vs Functon”

  1. Peter Harms July 5, 2011 2:01 pm #

    Hi John
    I am writing a paper on the “Three ‘Cs’ of IT” – complexity, continuity and credibility – wherein I am attempting to connect the ability/inability to manage complexity to the credibility of the ITO in the eyes of the organisation. The crux of the complexity problem is the uninhibited introduction of functionality into the IT equation. There is no comprehensive, or even comprehensible, work that I can find on the subject of IT functionality [and it is a term that I don't believe that we can avoid in IT]. I have been hunting and trawling for the past number of days now, with no success.
    Your approach has given me more than a glimmer of hope that I can complete this project in my lifetime! Thank you for a very refreshing, informative sojourn in a terribly confusing space!

  2. James McCully May 2, 2011 3:08 am #

    Why is the word, “functionality” needed when function is a noun. I often hear this word on design shows as in the “functionality of the room, or give the room functionality, or the room has no functionality.”? Why can’t it be, “the function of the room or gives it function.”? Functionality just seems like an unnecessary word. Is it a new word?

    • john May 23, 2011 12:19 am #

      Hi James

      You make a very good point. However, there tends to be a difference in meaning between ‘function’ and ‘functionality’.

      ‘Functionality’ tends to refer to more than merely the functions of an object, it also tends to describe how well or how badly the object carries out its intended functions. People will talk about the ‘functionality’ of a camera (for example) being good or bad. The functions will be standard, but the functionality can vary.

      In your example of a room, the function might be to deliver training. The functionality of that room might be bad, due to acoustics, furnishings, etc.

      My suggested definition for ‘functionality’, would be, “A definition of how well or how badly an object carries out is intended functions”.

      I hope that this helps.


  3. Jan van Bon August 31, 2010 8:06 am #

    so a Function tranfers some product input into some product output. That sounds like a process to me…: “A sequence of interrelated or interacting activities designed to accomplish a defined objective in a measurable and repeatable manner, transforming inputs into outputs.”

    Allow me to ask you another question:
    If a Business Function is a set of activities that delivers products, then what do you call a set of people, performing some core business activities, transferring some product input into a product output?

    • John Owens August 31, 2010 12:56 pm #

      Hi Jan

      The definition you give for a process is not quite specific enough and could lead it to be mistaken for a Function – this is the curse of the BPM world.

      A Process is the definition of the order of execution of Business Functions in response to a specific Trigger in order to arrive at a Preferred Outcome. All of the inputs and outputs for the Process will be those of the Functions making up the Process. Each Function can be part of one or more Processes. Read more on Process definition.

      In answer to your question; they are a set of people carrying out a Business Function. If you swap the set of people for a computer performing some core business activities, transferring some product input into a product output, then it is still a Business Function, but now being executed by a computer.

      This is where the term Capability can be useful. The Capability of and enterprise can increased by swapping the technology and/or resources used to carry out Business Functions.

      I cover Capability in response to another comment on this post below.


  4. Richard Ordowich August 31, 2010 3:00 am #

    I realize that defining terms is a difficult task but what I believe is important is when presenting a best practice for someone to use, the terms and decisions made such as deciding what to include and exclude in a business process model or any other model is critical. The guidance has to be precise not conceptual.

    It’s not clear how suggestions such as “As the answers above show, sometimes ‘yes’ and sometimes ‘no’” help? It’s like a “maybe” statement in a software program. How does one decide if you take the yes path or no path?

    This lack of precision suggests an ambiguity which is something we are all trying to avoid.

    I also am not clear on why a function is defined a “core activity”. What is the term for a “non-core activity”.

    • John Owens August 31, 2010 1:10 pm #

      Hi Richard

      Apologies if the phrase “sometimes ‘yes’ and sometimes ‘no’” caused confusion. What I should have written was “the circumstances in which each one is included have been defined above”, as I had already defined these.

      A “core activity” is any activity that an enterprise must perform in order to meet its objectives and continue in existence.

      I hope that this helps.


  5. Dennis Stevens August 31, 2010 1:53 am #


    For about the last decade I have been using Capabilities to be what you are calling Function here. A capability is something a business does – regardless of how they do it. The nice part of Capability is that it doesn’t change, even when the implementation changes. Capabilities help you overcome the “How Trap” when eliciting requirements, when planning systems releases, and when performing organizational improvements and designs. I used this concept at Microsoft to help develop their initial Business Architecture offering, Motion. And it is the subject of an HBR article I co-authored in June 2008, “The Next Revolution in Productivity” where we talk about Business Capability Modelling. Forester is now covering Capability Mapping as an approach to support Enterprise Architecture.I think it would be interesting to exchange ideas around this as you clearly have a strong body of knowledge supporting your Function Modeling approach.

    • John Owens August 31, 2010 6:45 pm #

      Hi Dennis
      I also use the term “Capability” but in a different way to the definition you gave. What a business does (more precisely what it OUGHT to do), regardless of the how it does it, I define as a Business Function. The different means by which a Function may be performed, I call “Mechanisms”. An example of this would be the Function “Accept Customer Order”. This could be carried out over the telephone, via fax or as an online transaction, i.e. three different Mechanisms for one Function.

      I align Capability with the standard English meaning of the word, i.e. what an enterprise is capable of doing and, in this sense, as with the title of your HBR article (which Dennis mentioned later in his comment), it may be associated with productivity. Capability couples a Function with elements that increase its depth, scope, productivity, etc. These elements could include knowledge, skills, technology, product portfolio, geography, and many others.

      I have written a further posts on this at Is Capability a Function?, Does Capability Equate to Process? and Capability vs Requirement

      Look forward to talking more on this.


      • Tory July 7, 2011 9:41 pm #

        This is way more hpelufl than anything else I’ve looked at.

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