1. CO6031 Systems Analysis for Health Informatics An Introduction to Methodologies

2. Concepts used for Analysis and Design
Methodologies provide guidelines to follow for completing every activity in SDLC
Models, whether physical, graphical or mathematical, are used to represent some aspect of the real world e.g DFDs and Gantt charts
Tools - usually software support to help create models
Techniques - a collection of procedures & guidelines to help analysts complete a systems development activity or task

3. What is a Methodology?
A methodology is a collection of procedures, techniques, tools and documentation aids, supported by a philosophy, which all help the systems developers in their efforts to implement an information system.
(Avison & Fitzgerald, 1988)
A methodology provides an integrated approach to systems development

4. Methodology Tools Techniques Models User interviewing techniques
CASE tools
Project Management applications
Word Processors
User interviewing techniques
Data Modelling techniques
Tools
Techniques
Models
Data Flow Diagrams
Entity-relationship diagrams
Use case diagrams

5. Systems Development Methodologies
A methodology comprises the following.
Phases & Sub-phases
Techniques & Tools
Guidance on how to use the techniques & tools at each stage within a phase or sub-phase
Specified deliverables
Project Management
An all encompassing philosophy

6. Methodologies Vary widely in: Philosophy
Completeness of definition or documentation
Coverage of the systems life cycle
Type of application to which they are best suited

7. Why the need for a Methodology? (1)
Aspects of early Information Systems
In applications development there was a far greater emphasis on programming than on understanding requirements
Poor communications between developers and end users
Users’ needs were often not properly established  systems developed tended to be inappropriate
Projects were generally ill-managed estimated completion dates (if any) were not met

8. Why the need for a Methodology? (2)
Systems were unreliable small changes to one part of the system could cause undesirable effects in other parts of the system
Often people who maintained the systems were not those who had developed it
Systems were not coherent; different applications did not interact since they were developed independently  redundancy and inconsistency in data
Systems might satisfy the needs of individual departments but not the needs of the organisation as a whole

9. Systems Development Methodologies – Examples (1)
SSADM (Structured Systems Analysis and Design Methodology)
(IE) Information Engineering
STRADIS(Structured Analysis, Design and Implementation of Information Systems)
OMT (Object Modelling Technique)

10. Examples (2) (SSM) Soft Systems Methodology
(JSD) Jackson Systems Development
ETHICS (Effective Technical and Human Implementation of Computer-based Systems)
(YSM) Yourdon Systems Method
Merise
Euromethod

11. Systems Development Methodologies
The following are not methodologies:
UML (Unified Modelling Language)
OO (This a software development approach or paradigm)
Formal Methods (the use of mathematical precision in specification and design)

12. Methodology: Advantages
The use of methodology helps to:
Produce a better quality product (documentation standards, acceptability to the user, maintainability and consistency)
Ensure that user requirements are met completely
Give the project manager a better control of the project execution and a reduction in overall development costs
Promote better communication between project participants
Encourage the transmission of know-how throughout the organisation

13. Methodology: Disadvantages
(depending on the Methodology) can be:
too restrictive, bureaucratic
followed like a cookbook (with potentially disastrous results)
too slow to deliver

14. Evolution of Methodologies
Pre-methodology era (-1970s)
Early-methodology era (1970s-1980s)
SDLC
Methodology era
methodologies emerged
Developed from practice - industry
Developed from theory – academia

15. Background to Methodologies (1)
>1000 brand-named methodologies exist world-wide
Often Practice-based & developed
An organisation practice  commercial product
Sometimes theory-based & developed
Developed in universities and research centres {commercial product}
Most early methodologies relied on one technique or closely related techniques (e.g. entity modelling, DFD)

16. Background to Methodologies (2)
Most methodologies developed into products were :
Written up
Made consistent
Made comprehensive
Made marketable
Updated as needed
Maintained
Researched and developed
Evolved into training packages
Provided with supporting software

17. Adopting a Methodology
Can range from a fully-fledged product to being a vague outline of the basic principles
Can cover widely differing areas of the development process, from high level strategic and organisational problem-solving, to the detail of implementing a small information system
Can cover just conceptual issues, or physical design procedures, or the whole range of intermediate stages

18. Adopting a Methodology (2)
A methodology also :
Can range from being designed to be applicable to specific types of problems in certain types of environments or industries, to being an all-encompassing general-purpose methodology
May be potentially usable by anybody, or only by highly trained specialists, (sometimes licensed practitioners) or be designed for users to develop their own applications and systems
May require an army of people to perform all the specified tasks, or may not even have any specified tasks
May or may not include CASE tools

19. Factors affecting the suitability of a Methodology
Project type (large, small, routine or mission-critical)
Control systems, or Information Systems?
Application domain (real-time, safety-critical, user-centred, highly interactive, distributed or batch-mode)
Nature and level of “maturity” of the IS development organisation:
Initial, repeatable, defined, managed, optimised