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SSM & Information Systems. Wilson’s approach to defining information requirements from conceptual models. Why SSM for IS? How has it been applied?. Understanding of the organisation , including cultural and political analysis . SSM Overview.

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SSM & Information Systems

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Ssm information systems l.jpg

SSM & Information Systems

Wilson’s approach to defining information requirements from conceptual models.

Why SSM for IS?

How has it been applied?


Ssm overview l.jpg

Understanding of the organisation, including cultural and political analysis

SSM Overview

Choosing & building models of “relevant systems” of purposeful activity, each based on a world-view

Finding out about the problem situation, including cultural/ political aspects

-

Taking action to improve ...

  • Debate the situation using the models (Comparison)

  • Identify systemically desirable and culturally feasible changes

  • Find accommodations between conflicting interests that will enable …


Ssm for is definition based on wilson s approach l.jpg

Maltese

Cross

Compare

models with

real world

Find out about

the problem

situation

Conceptual

models

Root

definitions

Define

information

categories

Define

activity-

activity

flows

Form

CPTM

To

design

SSM for IS definition: based on Wilson’s approach

Map to

organisation

(role-role

flows)

Map

activities

to IPP’s

(Adapted from Wilson, 1990)


Wilson s approach definitions l.jpg

Wilson’s approach - definitions

  • CPTM - Consensus Primary Task Model.

  • IPP = Information processing procedure - a current information system, automated or manual.

  • Maltese Cross - matrix technique for comparing information requirements of CPTM with real world information provision (IPP’s).

  • Role - a position in the organisation. Roles are responsible for activities.


Consensus primary task model cptm l.jpg

Consensus Primary Task Model (CPTM)

  • “What we are taking the organisation business processes to be.”(Wilson, 2001)

  • Still a Conceptual Model!

  • “The consensus of the problem-solving group that this is what they are taking the organisation unit to be doing (now or in the future).” (Wilson, 2001)

  • Various ways of producing this model.


Consensus models comparing models l.jpg

We can compare different (primary task) models based on different W’s.

One of these will be based on a neutral primary task description – something essential that no-one will dispute.

Consensus models - comparing models


Consensus models agreed activities l.jpg

100% consensus

Local

consensus

Neutral model

Consensus models - agreed activities

  • Take the neutral model’s activities

  • Examine other models’ activities

  • Add others after seeking agreement / accommodation

  • Choose activities that give a coherent model


Producing the cptm l.jpg

1 Produce initial

CPTM from

individual

models

2 Derive RD

from model

3 Derive test

model

from RD

5 Modify RD

and/or model(s)

Producing the CPTM

Individual

models

4 Compare test

model with tentative

consensus model

Consensus PTM

(CCTA, 1993)


Other ways of producing cptm l.jpg

Other ways of producing CPTM

  • Model the Mission Statement

    • Already agreed

    • Sometimes vague, seen as irrelevant, etc.

  • Extract it from a model of a wider system

    • If you have one

    • May be difficult to get a definable system from the gaps

  • Assemble it from smaller models

    • Within a general framework for organisations in system terms, into which they can fit – Wilson (2001) provides one


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Consensus models - do we need them?

  • We now have an agreed model - a consensus primary task model

  • Often regarded as essential precursor to defining information requirements

  • Why?

  • CPTM takes W’s into account when forming the model.

  • Some analysts believe that the variety of viewpoints should be preserved in information definition by continuing with multiple models.


Ssm for is definition based on wilson s approach11 l.jpg

Compare

models with

real world

Find out about

the problem

situation

Map

activities

to IPP’s

Conceptual

models

Root

definitions

Define

information

categories

Define

activity-

activity

flows

Form

CPTM

To

design

SSM for IS definition: based on Wilson’s approach

Map to

organisation

(role-role

flows)

(Adapted from Wilson, 1990)


Information categories l.jpg

Information categories

  • “Information = data + meaning.”

  • Information categories are therefore not just data items, but are defined in a way that indicates how they’re used.

    • E.g. “Stock availability” rather than “quantity”

  • Define the data in each category

  • Lower level models tend to have more detailed information categories.


Simple way to show information requirements l.jpg

Simple way to show information requirements

Available products

Purchase orders

3

Re-order goods

  • What information does it require?

  • What information does it produce?

Stock levels


Input output table l.jpg

Input/output table


Ssm for is definition based on wilson s approach15 l.jpg

Compare

models with

real world

Find out about

the problem

situation

Map

activities

to IPP’s

Conceptual

models

Root

definitions

Define

information

categories

Define

activity-

activity

flows

Form

CPTM

To

design

SSM for IS definition: based on Wilson’s approach

Map to

organisation

(role-role

flows)

(Adapted from Wilson, 1990)


Maltese cross l.jpg

Activities

from model

X

X

Do...

X

X

X

Store...

X

X

Find...

X

X

Issue...

X

Input

ICs

Output

ICs

IC1

IC6

IC6

IC5

IC4

IC3

IC2

IC1

IC2

IC3

IC4

IC5

X

X

X

Sales OP

X

X

Stock ctrl

Debtors

X

IPPs

Maltese Cross

N

E

W

S


Maltese cross17 l.jpg

Data

structures

Data

structures

Input

ICs

Output

ICs

Maltese Cross

Check order

Despatch

goods

Orders

Order

record

Stock

levels

Stock

card -

item no

& qty

Stock

levels

Stock

card -

item no

& qty

Orders

Order

record

N

S

E W

Item file -

quantity available

Item file -

quantity available

X

X

X

Sales OP

X

X

Stock ctrl

Debtors

X

Current IPPs


Organisational mapping l.jpg

Marketing

?

Marketing

asst

3

MD

5

1

Sales

Mgr

2

6

Salesperson

4

Sales-

person

8

Accounts

clerk

Sales Mgr

7

Sales

Accounts

Organisational mapping

  • What role is responsible for each activity?

Sales Mgr


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Wilson’s approach – summary (for you to read)

  • Derive primary task model(s) and gain consensus about these. (“Consensus primary task model”)

  • Derive the categories of information (sets of “data + meaning”) needed to support the activities, and the information categories produced by activities. Enter the categories into both East and West sides of a Maltese Cross, representing output and input.

  • Create the NW and NE matrices, relating the categories to the activities which will use and create them.


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Wilson’s approach - summary (2)

  • Take each existing Information Processing Procedure (IPP) and identify the information categories to which the input and output data belong. This gives the bottom half of the Maltese Cross.

  • Using the Maltese Cross, identify omissions, duplications etc. and define any necessary additional processes, avoiding duplication. (Wilson now does activity models of these new/changed IPP’s.)

  • Define management roles in terms of the activities for which each manager is decision-taker. Convert the “activity to activity” information flows into “role to role” information flows.


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Rationale (1)

  • “Systems analysis aimed at information systems design, if it is to make much impact, must first concentrate on the activity system which the information system is to serve.”

    (Checkland, Systems Thinking, Systems Practice)

  • So, we conceptualise the activity (served) system before the information (serving) system.


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Rationale (2)

  • Data is not information. Information involves attributing meaning, and can then inform action.

  • IS provide knowledge to support purposeful activities - hence people need to attribute meaning to the data, otherwise we just have a “data manipulation system”.

  • We need to understand what meaning people will give to data - hence useful to examine viewpoints, political factors etc.


Rationale 3 l.jpg

Rationale (3)

  • The activity system must contain activities which are feasible and seen as meaningful, and form a consistent whole.

  • We need to understand the organisational situation & the environment - a “rich understanding” is provided by SSM

  • We need to agree what this consistent, feasible & meaningful activity system consists of - SSM gives us a way to do this.


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Causes of IS failure

  • The wrong problem is addressed

  • Wider influences are neglected

  • Analysis is carried out incorrectly

  • Project undertaken for wrong reason

  • Users change their minds

  • External events change the environment

  • Implementation is not feasible

  • Poor project control

  • (See Bennett et al.section 2.3)


Ssadm 4 business modelling l.jpg

SSADM 4+ Business Modelling

An optional precursor to SSADM. Includes:

  • Business Activity Modelling

    • Business Perspectives (why)

    • Logical activity (what)

    • Business events (when)

    • Business Rules (how)

  • Work Practice Model

    • User roles (who)

    • Organisation structure & geography (where)

  • (See SSADM 4+ User Guide)


Business activity modelling l.jpg

Business Activity Modelling

  • Business Perspectives

    • What the business is trying to achieve

    • “To be a high-quality eco-tourism provider catering for niche markets”

    • May be several, sometimes conflicting

    • Used as basis for critical success factors, measures of performance

  • Sounds familiar?

  • Could be root definitions, perhaps several based on different W’s.


Logical activity model l.jpg

Logical Activity Model

  • Business activities that must be carried out and the dependencies between them

  • Modelled with control systems, feedback etc.

  • Sounds familiar?

  • Could be conceptual models, especially CPTM.


Ssm in business activity modelling l.jpg

SSM in Business Activity Modelling

  • SSM gives one possible approach – based on Wilson’s techniques

  • Create root definitions (Business perspectives included)

  • Derive Primary Task Models for essential activities

  • Derive Consensus Model

  • “Test against reality”

The RD is “What they believe their business to be.”

(SSADM4+ User Guide)


Link to requirements l.jpg

Link to requirements

  • Extract functional requirements from CPTM  Requirements Catalogue

  • Convert CPTM to required system Data Flow Model

    • Define external entities

    • Convert activities to processes within or outside system boundary (decompose?)

    • Identify information support where activities are outside boundary, & define system functions to provide it

    • Specify performance modelling data

    • Define data stores


Link to work practice l.jpg

Link to Work Practice

CPTM contributes to Work Practice Model

  • Identify activities that could be automated

  • Map onto organisation structure and geography

    • User roles

    • Locations

    • May need to decompose activities


Ssm in ssadm feasibility l.jpg

SSM in SSADM feasibility

  • SSM may be used

    • before a feasibility study

    • instead of a feasibility study

    • as part of a feasibility study

  • Detailed guidance published (CCTA, 1993)


Ssm deliverables in ssadm feasibility l.jpg

SSM deliverables in SSADM Feasibility

  • Help define the scope of the study (rich picture)

  • Suggest/confirm key entities for data model (RD)

  • Help decide what current systems analysis to do (RD, CM)

  • Identify functional & non-functional requirements (RD, CM, CPTM)

  • Identify & scope feasibility options (CM, Maltese Cross)

  • Identify information requirements & gaps in existing provision (Maltese cross, Information activity table)

  • Identify users

  • Help produce & check data flow models (CPTM, information categories)

  • Identify service levels and management information (measures of performance)


Ssm has also been used with l.jpg

SSM has also been used with…

  • UML – linked to use cases or activity diagrams

  • Other OO methods, (Schlaer-Mellor, Galvin & Lane (1999))

  • DFDs – several attempts (see Mingers, 1995)

  • Multiview – a method for small systems, with an SSM-based first phase. Also Multiview 2 – OO.

  • LOTOS (formal method)

  • JSD (Pre-OO method)

  • Information Engineering (for strategy planning)

  • Prototyping

  • etc.


Ssm is summary of uses l.jpg

SSM & IS – summary of uses

  • In information strategy planning

  • To decide what systems should be built

  • As an aid to scoping systems

  • In a feasibility study - or instead of one

  • For finding information requirements

  • To aid acceptance of systems

  • Dealing with IS-related problems


In these two weeks we have l.jpg

In these two weeks, we have

  • Learned the structure and techniques of SSM

  • Seen how to map SSM models onto information requirements using Wilson’s approach

  • Seen, briefly, some other uses of SSM in the IS field

  • Discussed why we might want to do this.


Follow up preparation l.jpg

Follow-up & preparation

  • Finish workbook (if you haven’t)

  • Prepare for seminar – section 7 of workbook

  • Further reading as specified in workbook, and dip into the items on Wilson’s approach.


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References & Further Reading

  • On Wilson’s approach –any of these is a good start.

    • Wilson, (1990), Systems: Concepts, Methodologies, and Applications, 2nd edn. Wiley. Chapter 6. (Or pp. 193-247 1st edn.)

    • CCTA (1993) Applying Soft Systems Methodology to an SSADM Feasibility Study, London: HMSO. Chapter 4.

    • Grant, K & Stansfield, M, “Matching Technology with Organisational Needs: Bridging the Systems Thinking Paradigm – A Practical Approach.” http://floti.bell.ac.uk/kevingrant/paper2.htm 


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References/Bibliography

  • Wilson’s approach

    • B. Wilson (2001), Soft Systems Methodology: Conceptual Model Building and its contribution, Wiley.

  • Overview of the field inc. Wilson, DFD.

    • J. Mingers (1995), ch. 2 in F. Stowell (ed), Information Systems Provision: the Contribution of Soft Systems Methodology, McGraw-Hill.

  • On rationale for using SSM for IS

    • M.C. Winter, D.H. Brown & P.B.Checkland (1995), “A role for soft systems methodology in information systems development,” European Journal of Information Systems4, pp. 130-142.


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References/Bibliography

  • SSADM

    • CCTA (1993) Applying Soft Systems Methodology to an SSADM Feasibility Study, London: HMSO. Chapter 4. (Reference book in library)

    • CCTA (1995), SSADM 4+ User Guide, NCC Blackwell

  • Multiview

    • D. E. Avison & G. Fitzgerald (1995), Information Systems Development: Methodologies, Techniques and Tools, McGraw-Hill. Section 6.2.

    • D.E. Avison & T. Wood-Harper (1990), Multiview, An exploration in Information Systems Development, McGraw-Hill.


References l.jpg

References

  • On Failure

    • Bennett, McRobb & Farmer, Object-Oriented Systems Analysis and Design using UML, McGraw-Hill. Section 2.3 (both editions)

  • OO approach

    • Lane, K. &Galvin, C. (1999) “Methods for Transitioning from Soft Systems Methodology (SSM) Models to Object Oriented Analysis (OOA), developed to support the Army Operational Architecture (AOA) and an Example of its Application.”

      http://www.dodccrp.org/1999CCRTS/pdf_files/track_6/092galvi.pdf[Viewed October 04]


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