MIS 210
Information Systems I
Lecture 2:
SDLC
Methodologies
Project Initiation and Planning
Requirements Analysis
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Systems Development
Life Cycle
(SDLC)
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Systems Development
What is a system?
A collection of related components that interact
to perform a task in order to accomplish a goal
Systems development (systems analysis and
design) is the process of creating systems,
developing them, and maintaining or enhancing
them.
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Characteristics of Software
• Software is developed, not manufactured
• Software does not “wear out”
– although it can become obsolete
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Today’s Software Development
Environment
• Failures
• Productivity gap
• Backlogs
• Maintenance bound
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Alleviating the Problems in
Systems Development
Elimination of the causes of system failure lie in
1.
2.
3.
4.
the application of methodologies
modeling tools
techniques
project management techniques
to design and build IS that not only meet the needs of the
users, but also are delivered on time and within budget
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Principles of Successful Systems Development
•
Get the user involved
•
Use a problem-solving approach
•
Establish phases and activities
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Establish standards for development and documentation
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Justify systems as capital investments
•
Don't be afraid to cancel or revise scope
•
Divide and conquer
•
Design systems for growth and change
•
Proper planning and project management
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Some Key Terms ...
• Systems development life cycle (SDLC): the life of a project,
from concept through implementation
• Methodology: a comprehensive and detailed version of an
entire SDLC
• Technique: an approach that applies specific tools and rules to
complete one or more phases of the methodology
• Modeling tools: specific tools used to apply techniques
• Project management techniques: tools used to help plan,
schedule, and control a project
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Tools
• Software support that helps create models
or other project components
• From simple drawing programs to complex
CASE tools
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Some Tools
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Project management applications
Drawing/graphics applications
Word processing/text editor
Computer-aided system engineering (CASE) tools
Integrated development environment (IDF)
Database management applications
Reverse-engineering tool
Code generators
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Techniques
• Collection of guidelines that help the analyst
complete a system development activity or task
• Step-by-step instructions
• General advice
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Some Techniques
•
•
•
•
•
Sylnovie Merchant, Ph.D.
Strategic planning
Project management
User interviewing
Data-modeling
Relational database design
MIS 210
Fall 2004
Systems Development Lifecycle (SDLC)
• Three major activities
– Analysis: understanding business needs
– Design: conceptualizing computer-system
solution
– Implementation: construction, testing, and
installation
• Two additional phases
– Project planning
– Support
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
The SDLC
F
r
o
n
t
e
n
d
B
a
c
k
e
n
d
1. Planning
a. Project identification and selection
b. Project initiation and planning
2. Analysis
a. Determine system requirements (WHAT users need)
b. Modeling possible solutions (HOW to satisfy user needs)
3. Design
a. logical design
b. physical design
4. Implementation
5. Maintenance / support
Sylnovie Merchant, Ph.D.
A
D
I
MIS 210
Fall 2004
SDLC Concepts
• All projects use some variation of the SDLC
• SDLC is more than phases
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–
–
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Principles of management
Planning and control
Organization and scheduling
Problem solving
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Major Attributes of the Life Cycle
• The project -– Moves systematically through phases where
each phase has a standard set of outputs
– Produces project deliverables
– Uses deliverables in implementation
– Results in actual information system
– Uses gradual refinement
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Project Phases
• Planning (Why build the system? How should
the team go about building it?)
• Analysis (Who uses system, what will it do,
where and when will the system be used?)
• Design (How will the system work?)
• Implementation (System delivery)
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Planning
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•
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•
•
Identifying business value
Analyze feasibility
Develop work plan
Staff the project
Control and direct project
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Design
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Design selection
Architecture design
Interface design
Data storage design
Program design
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Implementation
• Construction
– Program building
– Program and system testing
• Installation
– Conversion strategy
– Training plan
– Support plan
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Support Phase
• Objective: Keep system running productively
following initial installation
– End-user support
• Help desks
• Training programs
– Maintaining and enhancing computer system
• Enhancements
• Upgrades
• Maintenance
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Methodologies
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Common Development Methodologies
and Techniques

Code & fix model

Structured development

Prototyping

Rapid application development

Object-oriented development
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Code and Fix It Model
• An early technique
• The developer, in the following order:
–
–
–
–
codes
thinks about requirements
fixes the code
continues this process until...
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Structured Development
• Based on the principles of:
– modularization
– top-down decomposition
– process driven
• Structured programming
• Structured design
• Structured analysis
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Systems Development Life Cycle
Waterfall Model
Project Identification
and Selection
Project Initiation
and Planning
Analysis
Logical Design
Physical Design
Implementation
Maintenance
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Waterfall Model
• Problems
– dependent on documents, particularly in
completing the requirements and design phases
– tendency to hide poorly understood requirements
with elaborate specifications
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Advantages of Structured Development
• Been used successfully for over 30 years
• Provides a clear framework that defines and
divides important activities
• Can be applied to both small and large projects
• Division of labor is easier to facilitate
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Limitations of Structured Development
• Specification problems
– assumes that development is a sequential
process
• Changing requirements
– requirements specified at the beginning
– assumption that requirements will not change
• Conceptualization and visualization
– document led methodology
– volume of documentation can be huge
• Inaccuracy
– there is only downward trend
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Prototyping
• Principle: a user can tell you better what they DON'T want
than what they DO want
• Expendable (throw-away) prototyping:
– discarded after use
– used to support the analysis and design phases
• Evolutionary prototyping:
– prototype evolves into the final system
– is it a methodology?
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Advantages
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•
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Speed
Easier for end-users to learn
System changes discovered earlier
End-user involvement (ownership)
– increased user satisfaction
– increased user acceptance
• User-analyst communication
• Early problem detection
– reduced development time
– reduced maintenance
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Disadvantages
• Poor documentation
• Hard to control/manage
• (Unrealistic) User expectations
– time for final system
– final system differences
• reduced analysis
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Rapid Application Development
(RAD)
• Logistical approach to systems design
• Combines
– integrated CASE tools
– information engineering methodologies
– management techniques
• Speeds up Systems Development by as much as
20 times
• Critics consider it incomplete life cycle
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Object-Oriented (OO) Development
• A fundamentally new way of thinking about
developing systems
• Object-oriented: means that we organize
software as a collection of discrete objects that
incorporate both data and behavior
• Object-oriented development: an approach
to systems development that proposes the use
of objects in the building of new systems and
the rebuilding of old ones
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Advantages of OO
•
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Faster development
Higher quality
Easier maintenance
Increased scalability
Better information structure
Increased adaptability
Increased modeling power
Supports complexity
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Disadvantages of OO
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•
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Maturity of technology
Need for standards
Lack of database technology
Lack of reusable software
Lack of metrics
Speed of execution
Availability of qualified personnel
Cost of conversion
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Project Initiation and Planning
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Project Initiation and Planning
• Long-term information systems strategic plan
(top-down)
• Department managers or process managers
(bottom-up)
• Response to outside forces
– Legislative changes
– Market forces
– Competition
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Confirming Project Feasibility
•
•
•
•
•
Sylnovie Merchant, Ph.D.
Economic
Organizational and cultural
Technological
Schedule
Resource
MIS 210
Fall 2004
Intangibles in Economic Feasibility
• Costs and benefits cannot always be measured
• Examples
– Increased levels of service
– Survival
– Lost customers or sales
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Organizational and Cultural Feasibility
• Each company has own culture
• New system must fit into culture
• Evaluate related issues for potential risks
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Technological Feasibility
• Does system stretch state-of-the-art?
• Does expertise exist in-house for development?
• Does a third party need to be involved?
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Schedule Feasibility
• Can project be completed on time?
• Risk of schedule slipping
• Assumptions and estimates
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Resource Feasibility
• Team member availability
• Team skill levels
• Equipment
• Support staff
• Physical facilities
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Developing Project Schedule
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Task: smallest piece of work
Activity: group of tasks
Phase: group of activities
Schedule process
– List all tasks for each SDLC activity
– Estimate sizes of each task
– Determine task sequence
– Schedule tasks
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Project Staffing
• Develop resource plan for the project
• Identify and request specific technical staff
• Identify and request specific user staff
• Organize the project team into work groups
• Conduct preliminary training and team building
exercises
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Launching Project
• Oversight committee is finalized and meets to give
go-ahead
• Formal announcement made
• Key question, “Are we ready to start?”
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Focusing the Investigation
• Most system problems occur in complex
tasks that have high user impact
• Application complexity
• User impact
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Requirements Analysis
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Analysis
A. Determine system requirements
B. Structure requirements
– 1. Process modeling
– 2. Logic modeling
– 3. Data modeling
C. Select best alternative
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Requirements Analysis Goals
• Fully describe the current system
– Study and analyze the current system (gather
and study facts)
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•
•
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Determine the ideal information system
Identify resource constraints
Define and prioritize requirements
Inspire user confidence/ownership
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Study & Analyze Current System
• Gather information on what the system should
do from as many sources as possible
• Concentrate on WHAT is needed, not HOW to
do it
• “Don’t try to fix it unless you understand it”
• Major problem: analyst not understanding
user needs
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Study & Analyze Current System
1.
2.
3.
4.
-- Activities -Learn about current system (gather facts)
Model current system
Analyze problems/opportunities (study facts)
Establish new system objectives
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Study & Analyze Current System
-- Output -1.
2.
3.
4.
Complete statement of user environment
Models of current system
List of major problems/causes/effects
System objectives
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Learn About Current System
(gather facts)
Gather information from:
– Current information system:
• a current IS may exist
– External sources:
• reviewing other IS outside the organization can
reveal practical ideas and techniques
– Internal sources:
• single most important source of facts is the user
• existing paper work or documents is also a
good source
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Tactics
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Listen - don’t lecture
Don’t pre-solve problem
Compare stories
Look for reluctant responses
Observe your effects on system
Avoid politics (head nodding)
Expect hard, boring work
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Fact-finding Methods
• Research and site visits
• Existing documentation
• Observation
• Questionnaires
• Interviews
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Observation
• Not for long periods of time
– will change what your measuring
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•
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Vary observation periods
Take only minimal, preplanned notes
Coordinate visit beforehand
Beware of Selective Perception!!!
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Questionnaires
-- Types --
• Open-ended (free format)
• Closed-ended (fixed format)
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multiple choice
rating
ranking
single fact
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Questionnaire Development
1. Determine what facts need to be collected
2. Determine whether free- or fixed-format is best. Usually, a
combination is used.
3. Write the questions. Examine them carefully. Make sure
the questions don't reflect your personal biases.
4. Test the questions on a small sample of respondents.
Modify those questions that respondents had problems
with.
5. Duplicate and distribute the questionnaire.
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Questionnaires - the Good and the Bad
Advantages
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Can be quickly answered.
Cheap for gathering data from a large number of users.
Allow users to maintain anonymity.
Responses can be tabulated and analyzed quickly.
Disadvantages
– Number of respondents is often low.
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No guarantee that the user will answer all the questions.
Inflexible - voluntary information is stifled.
Elimination of body cues.
No immediate opportunity to clarify an answer.
Good questionnaires are difficult to prepare.
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Interviews
• Types of Interviews
1. Unstructured
2. Structured
• Types of Questions
1. Open-ended
2. Closed-ended
• Focus of Questions
1. Decision analysis
2. Data analysis
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
How to Conduct an Interview
1. Select interviewees. Learn as much as you can about
interviewee.
2. Make an appointment - never 'drop by'
3. Limit the interview to between 1/2 hour and 1 hour
4. Clear it with the interviewee's supervisor
5. Conduct the interview in a private location
6. Prepare for the interview: provide an interview agenda
7. Conduct the interview: opening, body, conclusion
8. Follow-up
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Interviewing Tips
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•
•
•
Watch the time
Don’t look at watch
No leading questions
Listen
No body language
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
More Interviewing Tips
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Make the user feel important
Be courteous and professional
Don’t take exhaustive notes
Use structured questions
Don’t ask users to remember details
Avoid gang interviews
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Interviews - the Good and the Bad
• Advantages
– Users are actively involved
– SA can probe for more feedback from user
– SA can reword questions for each interviewee
– Body cues
• Disadvantages
– Very time consuming, thus very costly
– Success of the interview is dependent on the SA's
human relations skills
– Interviewing may be impractical due to location of
interviewees
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Overall Strategy for Fact Finding
1. Learn all you can from existing documents
2. If appropriate, observe the system in action
3. Conduct interviews
4. Use questionnaires to clear up things you don't
fully understand
5. Follow-up
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Some Questions That Must be Answered
• What are the inputs to this system?
• What are the outputs of this system?
• What is the business process (i.e., how is data
processed)?
• Who are the direct end-users?
• How will the users feel about this system?
• Who developed the existing system?
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Analyze Problems / Opportunities
(study facts)
• Study and analyze the "current" system
• Problem analysis is difficult.
– We often try to solve problems without analyzing them.
– We try to state the problem in terms of a solution.
• Use the PIECES framework to frame your investigation of
the problems, opportunities, and requirements
– Performance analysis
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Information and data analysis
Economic analysis
Control and security analysis
Efficiency analysis
Service analysis
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
Requirements Analysis Document
• Parts
– How analysis was conducted
• credibility
• restarts
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User requirements
System constraints
Realistic System Objectives
Documentation
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004
User Requirements
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User system objectives (unedited)
Reports (type/frequency)
User training needs
Effect of system on various users
– Organization Chart
Sylnovie Merchant, Ph.D.
MIS 210
Fall 2004