Function Modelling - What Is It

Jul 16


John Owens

John Owens

  • Share this article on Facebook
  • Share this article on Twitter
  • Share this article on Linkedin

You are free to copy and send this article to whomever you think may find it of ... The only ... are that you copy and send it in its entirety and include all of the ... at th


You are free to copy and send this article to whomever you think may find it of interest. The only conditions are that you copy and send it in its entirety and include all of the resource
details at the bottom of the article each time you send it.

Many of the terms used in this article are standard terms used in the Integrated Modelling Method (IMM™) details of which can be found at the end of this article.

For a full colour version of this article complete with diagrams,
please send an email with "Request for Article 502 HTML" in the subject to:
Function Modelling! What IS That?
An article by John Owens
Creator of the Integrated Modelling Method (IMM™)
Function Modelling Is the Foundation of
All Business Modelling!
Knowing this one fact and keeping it foremost in your mind will enable you to build business models very quickly that are focussed,Function Modelling - What Is It Articles relevant, rigorous and easy to understand. If you start with any other model when doing business modelling you are off course - and may never get back!
Know Your Functions and You Know Your Business
This is another fact to keep foremost in your mind, because, from your business functions (commonly called 'functions') you can derive all of your other business models - including information and data models.
What is a Function?
But what is a business function? Here is a definition that you should commit to memory:
"A business function is an activity, or coherent set of activities, that a business must perform in order to meet its business objectives and continue in existence".
"It is what the business ought to be doing"
I use the term 'ought' as businesses are often doing things that are so far away from what they ought to be doing that it is a miracle that they continue to exist.
If you find out from business managers what the business ought to be doing and model this - as opposed to modelling anything else - then your models will enable the business to go to where it ought to be.
Example of business functions are:
Accept Order from Customer
Dispatch Goods to Customer
Accept Payment from Customer
Pay Suppliers for Good Received
Is a Function a Department?
The term 'function' is often incorrectly used to mean a department within a business. People will often refer to the 'Finance Function' when they really mean the 'Finance Department'. This misuse of the term should be avoided!
The term 'Finance Function' is still a valid term when used to mean 'all of the finance activities required to support the business'.
So what do you call the Finance Department? Easy, the 'Finance Department'!
Is a Function a Process
This is perhaps the most common and most serious area of confusion. Many (sadly far too many) analysts (and business people too) use the term 'process' when what they are actually referring to is a function.
Business functions and business processes are not the same thing. A business process is the definition of the order in which business functions are carried out in response to a trigger in order to achieve a desired outcome.
For an e-book describing process modelling in detail go to:
What is Function Modelling?
Function modelling is all about identifying, analysing and modelling business functions, independently of:
· how they are currently done
· who currently does them.
· the current organisation structure
The real power of Function Modelling is realised by concentrating on identifying, analysing and modelling what the business ought to be doing as opposed to how the business currently does things.
The main reason for this is that how things are done in a business can change dramatically over time (due to changes in such things as policy, technology, etc.) whereas what has to be done, by and large, remains the same.
The Stages of Function Modelling
In order for Function Modelling to be truly effective it must be done in a structured and ordered fashion. In all there are five distinct stages to Function Modelling:
· Information gathering
· Analysis and investigation
· Modelling
· Feedback
· Implementation
Because there are five stages this does not mean that function modelling takes forever. If done properly it can be done very quickly, but following the five stages ensures that it is not only done quickly but done correctly too!
For an e-book detailing the stages of function modelling go to:
Mechanisms and Functions
Mechanisms are the means by which functions are carried out. One of the most common errors in Function Modelling is to mistake mechanisms for Business Functions. The second most common error is to compound the first by continuing to model the mechanisms as opposed to identifying and modelling the underlying Business Functions.
A prime example of this is the mechanism 'Produce Invoice', which is nearly always modelled instead of the two Business Functions it represents, namely 'Charge Customer for Product Supplied' and 'Request Payment from Customer'.
Another set of mechanisms that are often mistakenly modelled as Business Functions are those based on reports. The mechanism 'Print Month End Sales Report' is a good example as it invariably appears on function hierarchies but it is not a Business Function but will be used by the business to perform a function.
When faced with this situation you must ask the business "what do you use this report for?". You might get a reply such as "It tells me what value of product we sold in each sales area". This gives you the function, namely:
"Analyse Sales of Product by Sales Area"
Here are more examples of functions and mechanisms.
Mechanism: ring customer with appointment·
Function: Make Sales Appointment with Customer
Mechanism: write to customer to make appointment· Function: Make Sales Appointment with Customer
Mechanism: produce month end report·
Function: Analyse Sales by Value for Specified Period
Function: Analyse Sales by Product Type and Region for Specified Period
Mechanism: produce invoice·
Function: Charge Customer for Product Supplied
Function: Request Payment from Customer
Mechanism: send chasing letter to customer·
Function: Request Payment From Customer
Mechanism: pass order form to warehouse·
Function: Authorise Dispatch of Product
Function: Function Catalogue
The function catalogue is one of the most powerful models that a business can have - for many reasons.
It is in essence a catalogue of all of the essential activities (functions) of the business.
The most effective way to display the catalogue is in the form of a function hierarchy as shown on the right.
(Diagram visible in HTML format - See End of Article)

We can use the diagram to explain some basic terms for function hierarchies.
1 = Root Function
2 = Grouping Function
3 = Atomic (or Leaf) Function
Elementary Business Function
An elementary business function (EBF) is a function which, once begun, must be completed or, if not completed, must be undone.
EBF's are what a business does on a day-to-day basis and may or may not be Atomic functions on the hierarchy.
Business process models should only be drawn using EBF's.
For an e-book describing how to build the Function Catalogue and the reasons why it is so powerful go to:
oFunction modelling is the foundation of all business modelling.
oKnow your functions and you know your business.
oA business function (=function) is what the business ought to be doing.
oA function is not a department.
oA function is not a process.
oMechanisms are the means by which functions (the what) are carried out - they are the how.
o The Function Catalogue is the most powerful model a business can own
If you would prefer to receive and read this article in HTML format, complete with coloured diagrams, then please send an e-mail with "Request for Article 502 HTML" in the Subject line to:
John Owens, the author of this article and the creator of the Integrated Modelling Method (IMM™), can be contacted at:
For more detailed information on the Integrated Modelling Method(IMM™) and e-books on all of the models and techniques described in this article are available at:
John Owens
Principal Consultant
SMART Consultancy & Training Services Ltd
Tel: +44 (0)1707 655981
Mobile: +44 (0)7734 935 635