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©LAWanninger 2001
Systems Development Life Cycle
• Introducing the SDLC (Systems Development Life Cycle)
• First Step: Strategic Analysis (of the Business) and Prioritization of Projects
• Strategic Importance
• Extent of Problem or Opportunity
• Analysis and Design (Prototyping)
• Construction
• Implementation
• Projects 1-5
• Cover the SDLC through Analysis and Design
• Illustrate the roles, responsibilities, and necessary interaction of IS and non-IS people
©LAWanninger 2001
GlobalInformation System
Architecture
IS Development Life Cycle (BUILDING IS)
BUSINESS AREAAnalysis
(Process/Data Flow Diagrams)
DATABASEDESIGN
(Data Model Diagram)
Computers &Communication
Networks
INFORMATION SYSTEM DESIGN- Application Processes
- User Interfaces (Forms+)
DATABASE(Related Tables)
CODE
STRATEGICCompetitiveANALYSIS
generate
executeread/write
define & populate
information requirements
PROCESSES
DATA PLATFORMPlanning
USERINTERFACE
©LAWanninger 2001
Information SystemsDevelopment Life Cycle
PLANNING&
ANALYSIS
DESIGN(MODELING)
CONSTRUCTION(GENERATION)
OPERATION&
MAINTENANCE
PRIORITIES, SCOPE
DESIGN DATABASE"REPOSITORY"
©LAWanninger 2001
Traditional SDLCISDEV
©LAWanninger 2001
The Systems Development Life Cycle (SDLC)
• PLANNING - global architectures, scoping, setting priorities• ANALYSIS - feasibility (technical, economic, operational),
- cost/benefit, - requirements - (WHAT)• DESIGN (synthesis) - (HOW)
Conceptual (business solution) Detailed design (IS solution)• Process modeling (DFD’s)• Data modeling (ER Diagrams)• User Interface (windows, menus, queries, forms, reports...)• Platform design (Computers + Communication Networks)
• CONSTRUCTION - definitions, programming, - (BUILD IT) - testing (unit, system, acceptance)
• INSTALLATION - conversion (direct cutover, parallel, pilot/phased)
• PRODUCTION / OPERATION --• POST-IMPLEMENTATION REVIEW• MAINTENANCE & ENHANCEMENT [& REPLACEMENT]
©LAWanninger 2001
SDLC - Overview and Metaphors
• Phase 1• Project Identification and Selection• Information Requirements & Systems
Analysis• System Design
• Phase 2• Construction, Testing• Implementation• Operation, Support, Maintenance
• QA – throughout• Get requirements right• Develop test cases• Minimize errors and cost• Maximize satisfaction and effectiveness
©LAWanninger 2001
A Marketing View of Information Systems
• SDLC – Life Cycle Model of IT Applications• Consumer Product Development – A
Metaphor for IT Applications• Software Requirements Determination
• MIS Theories 1 & 2• Systems Analysis & Design• Phased/Adaptive Development - "Learning"• Testing & QA• Implementation• Operation• Maintenance and Continual Improvement• Project Success Factors
©LAWanninger 2001
Cake & Frosting
©LAWanninger 2001
Consumer Product Development Metaphor
• Consumer Product Development Attributes• 20 - 30% Success Rate
• Find and Kill Failures Early• Evolution of successes throughout life cycle
• Profit & quality improvement• Proliferation
• Tie directly to business objectives• Lots of up-front time defining the product• Wide variety, series of Prototypes• Measurement & Iteration• Pilots for scale-up• KEY Players on the Team• Mix of creativity, new ways, business analysis,
marketing, expectations, manufacturing• Brand Management model – Matrix
©LAWanninger 2001
Evaluation - Formal Product and Market Research Methods
• Focus groups• Expert panels• Consumer panels• "Church basement" product evaluations• Mall intercepts• In-home tests• Mail consumer panels• Opinion research• Attitude and purchase intent measurement
• Secondary databases• Store scanner databases for product tracking
©LAWanninger 2001
Model of an IT Application
©LAWanninger 2001
Determining Information Requirements
• Two IS Theories• #1 - Managers do not know what information they need
• #2 - Most of the information you need to make a decision comes from outside your area
• Four major mistakes in determining information requirements• Viewing applications as functional
• Cross-functional, one function doesn’t know everything
• Conducting individual interviews • Limited perspective
• Asking wrong questions• Asking them - assumes they know!• Catalog - they ask for all
• Not allowing trial-and error• We must “learn" our requirements
©LAWanninger 2001
Approaches to Get Information Requirements Right
1. View systems as cross-functional• Conduct joint application design – multifunction
2. Broaden the perspective of input• Group vs. individual interviews
3. Ask Right Questions - Structured Interviews• CSFs - focus on business priorities• Ends & means - effectiveness & efficiency focus• Decisions – data needed and methods used• Describe your business process – steps, decisions,
data, errors, options and exceptions• Each of these help get at information requirements
of process, data and interfaces4. Provide means to help people learn their requirements
• Prototyping (Phased-Adaptive Development)• Learn from hands-on experience• View change positively vs. an enemy• Set user expectations & involvement
©LAWanninger 2001
Ends & Means Questions
• Efficiency
What is key to achieving efficiency?
How do you measure your efficiency?
• Effectiveness
What is key to operating effectively?
How do you measure your
effectiveness?
• What kinds of information help you achieve
or measure effectiveness or efficiency?
• Relate these questions to CSFs
©LAWanninger 2001
Decision Questions
• What kinds of decisions must you make - by
business process?
How important are those decisions?
How frequently do they occur?
• What information will help you make those
decisions?
How often do you not have which
information?
• Relate these questions and information needs to
CSFs
©LAWanninger 2001
Cost of Fixing System Defects
Require-ments
Design Develop Test & Debug
User Accept
Install0
20
40
60
80
100
120
140
160
Cost To "Fix System Defects"
©LAWanninger 2001
System Requirements & Design – Primary Source of "Defects" in Systems
• 2/3 of "System Defects" occur in the requirements and design phases• Not doing the "Right Thing",• Or not doing it the "Right Way”
• Problems:• Very high levels of maintenance and cost• Projects are late• Projects are over budget• People are unhappy and not satisfied with the
system or IS• Objectives and Actions:
1. Emphasize getting the requirements right, sooner - prototype, JAD, ask helpful questions, broad perspective
2. Find the errors sooner - QA and testing process3. Reduce the cost of fixing the errors - development
tools, flexible design, QA and testing process
©LAWanninger 2001
Concepts about the SDLC process
• Phased / adaptive development• Phased implementation• Expectations - managing & meeting• Prototypes
• Education, demos, breadth• Construction and testing• Pilot and scale-up• Evaluation
• Throughout, particularly prior to rollout• Group evaluation using marketing research
methods• Rollout
• Expect and seek out problems• Deal quickly with problems
• Anticipate and plan for continued development & change
©LAWanninger 2001
Output of Requirements Determination (P1)
• Relationship between Business and System Priorities
• General Requirements of the System• User Expectations
• Users and MIS people must then work as a team to make sure the "specifications" of a proposed system are "correct", both in terms of WHAT the system is to do, and HOW it is to do it.
• Users must "Correct" the Analysts' Representations
• Next step is systems analysis
©LAWanninger 2001
Systems Analysis & Design (P2-5)
• Study and model the existing business processes, information systems and information flows• Data flow diagrams, process flow diagrams, etc.• Communication vehicle between stakeholders
and implementers• What changes should be made to the processes?
• Study and model the data requirements, and determine the data creators, users and owners• Entity relationship diagrams• “Normalize” the data base for input efficiency• Communication vehicle between stakeholders
and implementers• Prototype to determine the primary interfaces for
the variety of users of the application (input and output)
©LAWanninger 2001
Systems Analysis & Design Models
• Process Design - (Project 2)• WHAT the system does• Process Model (Data Flow Diagram - Context)
• Data Design – (Project 3)• WHAT data will be maintained by the system• Data Model (Entity Relationship Diagram)
• User Interface Design – (Projects 4, 5, and more)• HOW the user will work with the system• Input - Screen layouts and forms, editing,
sequence, interface format, etc.• Output - Reports, queries, etc.• Prototype