Lecture 3Planning and Development Methodologies

BT2103

Developing Small Systemsfor Business

Definition Reasons for new system Traditional Systems Development

Lifecycle Analysis Techniques

The role of the systems analyst CSF’s and KPI’s

Types of methodology SSADM, SSM and RAD (Pro’s and Con’s)

Alternative solutions (Pro’s and Con’s)

Contents

From the Greek “Study of Methods”

A methodology can be defined as:“a collection of procedures, techniques, tools and documentation aids which help the systems developers in their aim to implement a new information system”

Avison and Fitzgerald (1996)

Definition

Current system can’t cope Time saving Cost saving Information for decisions Competitive advantage for organisation Competitive service for customers New technology image New legal requirements

Reasons for new system

5 Stage process: Investigation Analysis Design Implementation Maintenance

Traditional Systems

Development Lifecycle

Investigation

Analysis

Design

Implementation

Maintenance

Detect business problem/opportunity

Conduct feasibility study Cost vs. Benefits

Most costs are tangible, but most benefits are not

Develop project plan Obtain approval

Investigation

Information needs of end users. Current systems (computer or

otherwise) Develop functional requirements

Analysis

Procedure Narratives Data Flow Diagrams Entity Relationship Models

Analysis Techniques

Describes in basic steps exactly what happens in a process

Good for recording processes in detail

But Can be too detailed Does not show any dynamic relationships

Procedure Narratives

Shows relationships between entities and processes both inside and outside the system

Can have several layers of detail

Mainly used for ‘hard’ methodologies

Data Flow Diagrams

AKA Logical Data Models Show underlying meaning to DFD’s

Logical Data Structure Diagram and descriptions

Entity Life History Documents stages of entity development

Entity Relationship

Diagrams

Specify: Hardware Software Users Data resources Information products (reports etc.)

Design

Acquire components Convert data Test system Train users Make new system operational

Different methods: Parallel, Phased, Cut Off Pro’s and Con’s

Implementation

Review system’s functions Gain user’s feedback Monitor Evaluate Modify where necessary

Maintenance

Investigation of the existing system

Managing the feasibility study

Conceptual design (logical)

Overseeing the testingCoordinating the

implementationEvaluation of the system

performance

Must be a good communicator

The role of The Systems Analyst

Critical Success Factors: Operational goals

Hospital – We need to use our Operating Theatres more effectively

Key Performance Indicators: Measurement of success

Hospital – Number of hours OT is idle

- Number of operations performed - Are numbers enough?

CSF’s and KPI’s

Types of Methodology

Business problem/opportunity

Exploration of problem

Fully explore what is needed

Full design brief

Design

Build

Implement

RAD

ETHICS

SSADM

SSM

IE

Expanded the 5 point list to 7 (version 4) Feasibility Investigation of current environment Business system options Definition of requirements Technical system options Logical design Physical design

SSADM

Benefits Excellent where requirements are defined

and structured

Disadvantages Time consuming Costly Inflexible

Benefits and Disadvantages

‘An organised way of tackling a messy situation’ (Checkland and Scholes)

Developed to help with unstructured and poorly defined problems

Centres on individual’s experiences of the problem

Therefore, ‘right information’ rarely exists

SSM

Situation considered problematic Problem expressed Definition of purposeful activity Conceptual systems models Comparison (model to real world) Changes Action to improve problem

situation

Stages in SSM

(Systems thinking)

(Real world)

(Real world)

SDLC Problems

Prototyping (RAD) Application Software Packages End – User Development Outsourcing

Alternative Solutions

An experimental system, put together quickly for feedback from users

The prototype is a working version of all or part of the system

Users’ requirements are met by constant refining through iterative processes

Prototyping (RAD)

Prototyping RAD

Identify basic requirements

Develop a working

prototype

Use the prototype

User feedback positive?

Revise the prototype

Operational prototype

No

Yes

Viable alternative to some bespoke systems development Off-the-shelf packages for more and more solutions

Implementation time and costs greatly reduced May not meet all requirements

Application Software Packages

Increasingly used in today’s organisations Easier to define user requirements Benefits:

Increase in user satisfaction / productivity

Disadvantages: Documentation? Managerial control? Ownership

End – User Development

The hiring of an external organisation Benefits:

Reduces need for IS department Accommodate fluctuating needs

Disadvantages: Loss of control over:

Technology Competitive advantage Own IS function

Outsourcing

The development of a system should be managed through the use of a suitable methodology

As many different development methodologies exist as there are systems Alternative approaches such as EUD and outsourcing exist The whole process should be managed by a systems analyst

Conclusion