Business functions in TOGAF and ArchiMate

Copyright 2017 Graham Berrisford.

One of about 300 papers at http://avancier.website. Last updated 29/01/2017 19:26

Contents

Preface. 1

What TOGAF means by “function”. 2

Function and Capability in TOGAF. 3

What other sources mean by “function”. 4

What ArchiMate means by “function”. 4

Conclusion. 6

Preface

EA regards the enterprise as a system.

This table defines some general system theory concepts and illustrates their application in business architecture approaches.

It distinguishes structures from behaviors, and abstract structures from concrete ones.

System theory		Business architecture in BIZBOK®	Business architecture in TOGAF®
Abstract structure node	groups required behaviors/actions	Capability	Function, Role
Concrete structure node	is assigned to perform behaviors/actions		Organization unit, Actor
Abstract behavior	sequences required behaviors/actions	Value stream: steps in value creation/delivery	Scenario, Process: steps in service creation/delivery
Abstract action	is an atomic behavior		Process step
Abstract system structure	the network in which nodes interact	Capability/Outcome Network: Flows between Capabilities.	Node Connectivity Diagram: Flows between Nodes

What TOGAF means by “function”

In short, a function is a logical business component, a logical unit of business capability, requiring physical organisational resources to be implemented.

E.g. the core functions of a bank include marketing, sales, branch management, card payments, and support functions like human resources.

Functions are usually arranged in a hierarchical structure, a logical organisation chart.

What TOGAF says	What TOGAF means
“Function describes units of business capability at all levels of granularity”	A function describes a unit of business capability, at whatever level of granularity is appropriate to the architecture work.
“Any bounded unit of business function should be described as a function.”	Any bounded unit of business capability should be described as a function.
“Function is bounded by service"	A function is bounded and definable by the services it offers (its service portfolio). A business service provides materials and/or information of value to the service requester.
“Business functions are supported by business services with explicitly defined boundaries and will be supported and realized by business processes.”	Business functions are bounded by the services they offer to each other and to external entities. Each business service is defined by a service contract. The contract defines what materials and/or information of value are provided to the service requester. A business service is realized by one or more business processes. Those processes may be wholly contained within one function. Or else, that function may request services from other functions.
“Business functions are performed by organizational units.”  “Structured Analysis: Identifies the key business functions within the scope of the architecture, and maps those functions onto the organizational units within the business.”	In a “functional organization structure” the function-organization unit relationship may be one to one. But in general (since both can be composed and decomposed) the relationship is many-to-many.  Structured analysis also defines how processes cross and connect the bottom-level functions in the function hierarchy.
“The purpose of the Functional Decomposition diagram is to show on a single page the capabilities of an organization that are relevant to the consideration of an architecture. By examining the capabilities of an organization from a functional perspective, it is possible to quickly develop models of what the organization does without being dragged into extended debate on how the organization does it. Once a basic Functional Decomposition diagram has been developed, it becomes possible to layer heat-maps on top of this diagram to show scope and decisions. For example, the capabilities to be implemented in different phases of a change program.”	A functional decomposition: · is a logical business structure, to which other architectural entities can be mapped. · arranges business functions/capabilities in a hierarchical structure. · structures what the business does, in progressively more detail at each level of the hierarchy. · enables people to start with a broad discussion and then dive into more detail where needed. · is defined using function/capability names that help to establish a common vocabulary across the business. · is analyzed to identify functions/capabilities that require improvement - often color-coded as a “heat” map. · is more stable than the business processes and organization’s management structure.

Function and Capability in TOGAF

The capability-based planning chapter in TOGAF 9.1 was written with little regard to TOGAF products and techniques, and is vague.

However, the quotes in the table below show that TOGAF regards functions and capabilities as synonymous. 

	What TOGAF says about Functions	What TOGAF says about capabilities
	“The Business Service/Function catalog can be used to identify capabilities of an organization.”	“A business capability can be thought of as a synonym for a macro-level business function.” “An ability that an organization, person, or system possesses.”
Specification	“Any bounded unit of business function should be described as a function.” “Business functions are supported by business services with explicitly defined boundaries and will be supported and realized by business processes.” “Function is bounded by service [should be services].”	“Typically expressed in general and high-level terms”
Examples	“electronic commerce, supply chain management, etc.”	“marketing, customer contact, or outbound telemarketing.” “finance capability.”
Implementation by organisation	“Business functions are performed by organizational units.” “Structured Analysis: Identifies the key business functions within the scope of the architecture, and maps those functions onto the organizational units within the business.”	“Typically require a combination of organization, people, processes, and technology to achieve.”
Independence of organisation structure	“The purpose of the Business Interaction Matrix is to depict the relationship interactions between organizations and business functions across the enterprise.” “The Federal Enterprise Architecture Business Reference Model is a function-driven framework for describing the business operations of the Federal Government independent of the agencies that perform them.”	“A business capability assessment is used to define what capabilities an organization will need to fulfil its business goals and business drivers.”

What other sources mean by “function”

This table lists what function means in various sources.

In this source	Function	E.g.
Structured analysis	Abstract active structural element – a component in a logical composition structure	Marketing, account management, product management
TOGAF 9.1	Ditto.	Ditto
IT4IT	Ditto (“functional component”).	Ditto
ArchiMate 3.0	Ditto, but wrongly presented as a behavioural element	Ditto
DoDAF	Not defined, because it uses capability instead	Ditto
VDML 1.0	Not defined, because it uses capability instead	Ditto
Ackoff	An ideal, objective or purpose and/or the behaviors that achieve them.	to survive , to reproduce, to win the game
UML 2.4.1	A behavioral element - a primitive stimulus-response process	given a radius, respond with the area

In mathematics, a function is a process that relates an input to an output; it relates each element of a set with exactly one element of another set (possibly the same set).

In UML, a function is a primitive process that transforms a set of input values to a set of output values without reference to system state.

In both cases, the function uses only input values to computes output values; it does not maintain stored data and has no other effect or side effect.

Functionality is an ugly word, often replaceable by “behaviour” or “functions” with no loss of meaning.

E.g. the UML standard uses “functionality” to mean the group of services/processes found in an interface.

What ArchiMate means by “function”

ArchiMate defines three application architecture elements using the term “functionality”.

And defines the fourth (“application function”) using the term “behaviour” instead.

ArchiMate Application Domain	Behavioural view	Structural view
External view	Application Service an “externally visible unit of functionality” which “exposes the functionality of components”	Application Interface “describes the functionality of a component
Internal view	Application Functions “describes internal behaviour”.	Application Components “self-contained unit of functionality”

ArchiMate uses the term business function in the structural sense that TOGAF does (distinct from business process).

But its application function appears to be a process, encapsulated by an application service (which you might call a use case).

And confusingly, ArchiMate uses the term “business function” for a behavioural element.

The standard ArchiMate example of “application behaviour” shows functions arranged in a sequential process that runs from trigger to result – in which it appears each function is a sub process.

It appears that the “function” symbol in an ArchiMate diagram may represent either a process (documentable using a flow chart) or a logical component (documentable as an actor/component definition).

A function (like a role) can be defined internally by the process it performs.

For a while, I positioned Functions thus in the generic meta model.

TOGAF’s Business Domain	Behavioural view	Structural view
External view	Business Services.	???
Internal view	Business Processes	Business Functions

A function (like a role) can also be defined externally by the services it can provide.

After a long discussion with Marc Lankhorst, I concluded functions would be better placed thus.

TOGAF’s Business Domain	Behavioural view	Structural view
External view	Business Services.	Business Functions
Internal view	Business Processes	Business Actors

Eventually, in aligning TOGAF with ArchiMate, I concluded the meta model would be better extended thus.

TOGAF’s Business Domain	Behavioural view	Logical structural view	Physical structural view
External view	Business Services.	Business Functions	Organisation Units
Internal view	Business Processes	Business Roles	Business Actors

Conclusion

Business functions are abstract active structural elements.

They are logical abstractions from real organisation units, and if defined by services offered, can be seen as interface definitions.

Business capabilities correspond to business functions.

But the term capability often implies the function + goals + human and other resources needed to realise the function.

Which is to say – a capability is a business system.

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