Transcript Chapter 3 Study Tool - High Point University

Chapter 3
Requirements Modeling
Phase Description
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Systems analysis is the 2nd of 5 phases
in the systems development life cycle
(SDLC)
Uses requirements modeling and
enterprise modeling to represent the
new system
Before proceeding to the next phase,
systems design, consider some system
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development strategies
Chapter Objectives
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Describe systems analysis phase activities and
the end product, system requirements document
Understand joint application development (JAD)
and rapid application development (RAD)
List and describe system requirements, including
outputs, inputs, processes, performance, and
controls
Explain the importance of scalability in system
design
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Chapter Objectives
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Define total cost of ownership (TCO)
and explain the concept
Conduct a successful interview
Develop effective documentation
methods to use during systems
development
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Introduction
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Requirements modeling techniques (factfinding) and team-based methods
(JAD/RAD) are tools that systems analysts
use to visualize and document new systems
System requirements and fact-finding
techniques are interviewing, documentation
review, observation, surveys and
questionnaires, sampling, and research
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Systems Analysis Phase
Overview
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Uses models and
other documentation
tools to visualize and
describe the
proposed system
The deliverable is a
system requirements
document
Figure 3-2
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Systems Analysis Phase
Overview
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Systems Analysis Skills
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Analytical skills
Interpersonal skills
Team-Oriented Methods & Techniques
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Joint application development (JAD) (user involved)
Rapid application development (RAD) (mini SDLC)
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Joint Application Development
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User Involvement
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Users have a vital stake in an information
system and they should participate fully
Successful systems must be user-oriented
and users need to be involved
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Joint Application Development
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JAD Advantages and Disadvantages
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More expensive and can be cumbersome
Allows key users to participate effectively
When properly used, JAD can result in a
more accurate statement of system
requirements, a better understanding of
common goals, and a stronger commitment
to the success of the new system.
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Rapid Application
Development
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Is a team-based technique that speeds
up information systems development
and produces a functioning information
system
Relies heavily on prototyping and user
involvement
Project team uses CASE tools to build
the prototypes and create a continuous
stream of documentation
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Rapid Application
Development
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RAD Objectives
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To cut development time and expense by
involving the users in every phase of
systems development
Successful RAD team must have IT
resources, skills, and management support
Helps a development team design a system
that requires a highly interactive or
complex user interface
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Rapid Application
Development
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RAD Advantages and Disadvantages
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Systems can be developed more quickly
with significant cost savings
RAD stresses the mechanics of the system
itself and does not emphasize the
company’s strategic business needs
Might allow less time to develop quality,
consistency, and design standards
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Modeling Tools and
Techniques
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Unified Modeling Language
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A widely used method of visualizing and
documenting software systems design
provides various graphical tools and
techniques, such as use case diagrams and
sequence diagrams
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Modeling Techniques
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Functional Decomposition Diagrams
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A top-down representation of business
functions and processes
Also called structure charts
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Modeling Techniques
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Functional Decomposition Diagrams
Figure 3-9
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System Requirements
Checklist
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System requirement
Five general categories
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Outputs
Inputs
Processes
Performance
Controls
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Future Growth, Costs, and
Benefits
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Scalability
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A scalable system offers a better return on
the initial investment
To evaluate, you need information about
projected future volume for all outputs,
inputs, and processes
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Future Growth, Costs, and
Benefits
Total Cost of Ownership
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In addition to direct costs, systems developers must
identify and document indirect expenses that
contribute to the total cost of ownership (TCO)
Formula: cost of design, cost of implementation, cost
of editing, cost to replace
Plus number of users x days in year used x years
before replaced x salary x extra time used per day.
Plus lost customer good will, plus lost business.
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Cost and Benefits
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Tangible verses Intangible cost
Direct verses Indirect Costs
Fixed verses Variable Costs
Overhead Costs
Development verses Operational Costs
Profit verses Cost Center
Chargeback methods
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Cost and Benefits
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ROI – Return on Investment
Benefit – costs = ratio %
Total costs
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Net Present Value Analysis
NPV = total present value of benefits
– total present value of costs
(factored for inflation)
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Fact-Finding
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Overview
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Although software can help you to gather
and analyze facts, no program actually
performs fact-finding for you
The first step is to identify the information
you need
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Fact-Finding
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Who, What, Where, When, How, and
Why?
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Interview
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Step 1: Determine the People to
Interview
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Informal structures
Step 2: Establish Objectives
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Determine the general areas to be
discussed
List the facts you want to gather
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Interviews
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Step 3: Develop Interview Questions
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Creating a standard list of interview
questions helps to keep you on track and
avoid unnecessary tangents
Avoid leading questions
Open-ended questions
Closed-ended questions
Range-of-response questions
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Interviews
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Step 4: Prepare for the Interview
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Careful preparation is essential because an
important meeting and not just a casual
chat
Limit the interview to no more than one
hour
Send a list of topics
Ask the interviewee to have samples
available
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Interviews
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Step 5: Conduct the Interview
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Develop a specific plan for the meeting
Begin with good introduction
Use engaged listening
Allow the person enough time to think
about the question
Summarize main points
After interview, summarize the session and
seek a confirmation
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Interviews
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Step 6: Document the Interview
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During the interview, note taking should be
kept to a minimum
After the interview, record the information
quickly
After the interview, send memo expressing
appreciation, including the main points
discussed so the interviewee has a written
summary and can offer additions or
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corrections
Interviews
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Step 7: Evaluate the Interview
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In addition to recording the facts obtained
in an interview, try to identify any possible
biases
Unsuccessful Interviews
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No matter how well you prepare for
interviews, some are not successful
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Other Fact-Finding Techniques
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Document Review
Observation
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Seeing the system in action gives you
additional perspective and a better
understanding of the system procedures
Plan you observations in advance
Hawthorne Effect
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Other Fact-Finding Techniques
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Questionnaires and Surveys
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Keep the questionnaire brief and userfriendly
Provide clear instructions that will answer
all anticipated questions
Arrange the questions in a logical order,
going from simple to more complex topics
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Other Fact-Finding Techniques
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Questionnaires and Surveys
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Phrase questions to avoid
misunderstandings; use simple terms and
wording
Try not to lead the response or use
questions that give clues to expected
answers
Limit the use of open-ended questions that
are difficult to tabulate
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Other Fact-Finding Techniques
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Questionnaires and Surveys
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Limit the use of questions that can raise
concerns about job security or other
negative issues
Include a section at the end of the
questionnaire for general comments
Test the questionnaire whenever possible
on a small test group before finalizing it
and distributing to a large group
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Other Fact-Finding Techniques
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Sampling
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Systematic sample
(every 10th customer for
review)
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Stratified sample (% of transactions/shift)
Random sample (any 20)
Main objective of a sample is to ensure
that it represents the overall population
accurately
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Other Fact-Finding Techniques
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Research
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Newsgroups
Site visit
Figure 3-23
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Other Fact-Finding Techniques
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Interviews versus Questionnaires
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When you seek input from a large group
questionnaire is a very useful tool
If you require detailed information from
only a few people, then you probably
should interview each person
Interview is more familiar and personal
Questionnaire gives many people the
opportunity to provide input and
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suggestions
Documentation
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The Need for Recording the Facts
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Record information as soon as you obtain it
Use the simplest recording method
Record your findings in such a way that
they can be understood by someone else
Organize your documentation
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Documentation
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Software Tools
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CASE tools
Word processing
Spreadsheets
Databases
Figure 3-24
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Preview of Enterprise
Modeling
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At the conclusion of requirements
modeling, systems developers should
have clear understanding of business
processes and system requirements
The next step is to model the logical
design of the system
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Chapter Summary
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The systems analysis phase includes three
activities
The main objective is to understand the
proposed project and build a solid foundation
for the systems design phase
The fact-finding process includes interviewing,
document review, observation, questionnaires,
sampling, and research.
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Chapter Summary
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Systems analysts should carefully record
and document factual information as it is
collected, and various software tools can
help an analyst visualize and describe an
information system
Chapter 3 Complete
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