COSC 2810 Systems Analysis and Design
Phase 2 : Systems Analysis (Chapter 3, 4, 5)
Chapter 3: Requirements Modeling
Chapter 4: Enterprise Modeling
Chapter 5: Development Strategies
Chapter 3: Requirements Modeling
● After system planning (Phrase 1), an
sys. analyst needs to use requirements
models to describe the new sys. This
chapter describes modeling techniques
and team-based methods to visualize
and document the new
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sys.
Phase 2 System Analysis:
● Systems analysis is the second of five
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, a sys. analyst will
consider system development strategies
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Chapter Objectives
● Describe systems analysis phase
activities and the end product of the
systems analysis phase(A system
requirements document)
● Understand joint application development
(JAD) and rapid application development
(RAD)
● Explain how systems analysts use a
functional decomposition diagram (FDD)
● Describe the Unified Modeling Language
(UML) and use case diagrams and
sequence diagrams
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Chapter Objectives
● List and describe system requirements,
including outputs, inputs, processes,
performance, and controls
● Explain the importance of scalability in
system design
● Use fact-finding techniques, including
interviews, documentation review,
observation, questionnaires, sampling,
and research
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Chapter Objectives
● 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
● This chapter describes requirements
modeling techniques and team-based
methods that systems analysts use to
visualize and document new systems
● The chapter discusses system
requirements and fact-finding
techniques, which include interviewing,
documentation review, observation,
surveys and questionnaires, sampling,
and research
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Systems Analysis Phase Overview
● Use models and
other
documentation tools
to visualize and
describe the
proposed system
● The deliverable is a
system
requirements
document
● Sys. analysis phase
includes 3 main
Figure 3-2
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Systems Analysis Phase Overview
● Requirement modeling involves fact-finding to
describe the current sys. and identify the
requirements of the new sys.
● Systems Analysis Skills
– Analytical skills(Id a problem,evaluate key
elements of the problem, and develop a
solution.)
– Interpersonal skills (communicating people at
all levels)
● Team-Oriented Methods and Techniques
– Joint application development (JAD)
– Rapid application development (RAD)
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Joint Application Development (JAD)
- A fact finding technique that brings user into
development process as active participants.
● User Involvement
– Users have a vital stake in an
information system and they should
participate fully
– Successful systems must be useroriented and users need to be involved
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Joint Application Development
● JAD Participants and Roles
Figure 3-4
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Joint Application Development
Sys development is a joint effort:
Figure 3-5
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Joint Application Development
● JAD Advantages and Disadvantages
– More expensive and can be cumbersome
(large team)
– 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
(RAD)
● Is a team-based technique that speeds up
information systems development and
produces a functioning information
system
● Relies heavily on prototyping and user
involvement (allow user to exam a model
at early developing stage)
● Project team uses CASE tools to build the
prototypes and create a continuous
stream of documentation
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Rapid Application Development
● RAD Phases (4) and Activities
Requirements planning, User design,
Construction, Cutover
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Figure 3-7
Rapid Application Development
● RAD Objectives
– To cut development time and expense
by involving the users in every phase of
systems development (reduce cost of
change)
– Successful RAD team must have IT
resources, skills, and management
support
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Rapid Application Development
● RAD Advantages and Disadvantages
– 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
(meet short term purpose, scarifies long
term goals)
– Might allow less time to develop quality,
consistency, and design standards
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Modeling Tools and Techniques
● CASE Tools: Popkin’s eg. :business
enterprise model, a business process
model,an organization model, a location
model, an application model, a data
model and a technology model.
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Figure 3-8
Modeling Tools and Techniques
● Functional Decomposition
Diagrams(FDD)
– A top-down representation of business
functions and processes, also called
structure charts
– Start at the top and work way down.
During requirement modeling, FDD is
used to model business functions and
show how they are organized into lowlevel process. Those processes are
used as logical symbols and can be
translated into program modules during
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application development
Modeling Tools and Techniques
● Functional Decomposition Diagrams
Figure 3-9
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Modeling Tools and Techniques
● Unified Modeling Language (UML)
- uses OOP design concepts
– 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 Tools and Techniques
● Unified Modeling Language:
case diagrams: visually represent the
interaction between users and info. sys.
Figure 3-10
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Modeling Tools and Techniques
Unified Modeling Language
Table documents for F. 3-10
Figure 3-11
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Modeling Tools and Techniques
Unified Modeling Language
Sequence Diagrams: shows timing
transactions between objects.
Sequence Diagram
Figure 3-13, vertical timeline of
a successful credit card
validation
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System Requirements Checklist
● During requirement modeling, must
describe all sys. requirements, which
serve as benchmarks to measure the
overall acceptability of finished sys.
● Five general categories
– Outputs
– Inputs
– Processes
– Performance
– Controls
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System Requirements Checklist
examples of Outputs:
● A purchasing sys must provide
suppliers with up-to date specifications.
● An inventory sys. Must produce a daily
report showing part no. quantity on
hand, quantity available and unit cost
● A contact management sys. Must
generate a daily reminder list for all
sales reps.
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System Requirements Checklist
examples of Inputs
● Input patient services into billing sys. in
a hospital
● Teachers must enter grades online
● Mgr must enter overtime hour sheet for
payroll sys.
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System Requirements Checklist
examples of Processes
● Student records sys. must allow access
by entering ID or name
● Human resources must interface with
payroll sys.
● Bank must reject over-limit loans
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System Requirements Checklist
examples of Performance
● Online retailer must be operational 24
hours, 7 days
● Response time to user should be
relatively short
● Online inventory sys must flag lowstock items.
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System Requirements Checklist
examples of Controls
● Provide logon security limit access
● File access control
● Order approval by mgr
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Future Growth, Costs, and Benefits
● Scalability: a system’s ability to handle
increased business volume and transactions in
the future
– 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. eg 1: to ensure an online hotel
reservation sys. to work for years of operation,
you should forecast the frequency of online
queries and estimate turnaround and response
time.
eg 2: You need to exam current data storage to
predict future needs for upgrading current sys.
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configuration or HW
Future Growth, Costs, and Benefits
● Total Cost of Ownership
– In addition to direct costs, systems
developers must identify and document
indirect expenses (user support,
downtime productivity losses) that
contribute to the total cost of ownership
(TCO)
– Microsoft has developed a method for
measuring total costs and benefits,
called Rapid Economic Justification
(REJ), F. 3-14, p. 103
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Specific Fact-Finding processes:
● Overview
– Although software can help you to gather and
analyze facts, no program actually performs
fact-finding for you
– Fact-finding techniques: interviews, document
review, observation, surveys,
questionnaires, sampling and research
– The first step is to identify the information you
need, ie. start with a fact-finding plan involving
types of who, what, where, when, why and
how questions
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Fact-Finding
● Who, What, Where, When, How, and
Why?
Figure 3-15
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Fact-Finding
● The Zachman Framework (1980s) for
enterprise architecture
– A model that asks the traditional factfinding questions in a systems
development context
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Fact-Finding
see eg. on p. 105 or refer to
government.popkin.com/frameworks/
zachman.htm
Figure 3-16
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Interviews
● Systems analysts spend a great deal of
time talking with people
● Much of that time is spent conducting
interviews
● Consists of 7 steps
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Interview
● Step 1: Determine the People to
Interview
– Informal structures
● Step 2: Establish Objectives
– Determine the general areas to be
discussed
– List the facts you want to gather
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Interviews
● Step 3: Develop Interview Questions
– 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
● Step 4: Prepare for the Interview
– 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
Memo eg. p. 108
Figure 3-18
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Interviews
Figure 3-19
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Interviews
● Step 5: Conduct the Interview
– 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
● Step 6: Document the Interview
– 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 corrections
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Interviews
● Step 7: Evaluate the Interview
– In addition to recording the facts
obtained in an interview, try to identify
any possible biases
● Unsuccessful Interviews
– No matter how well you prepare for
interviews, some are not successful
(deliberate info hiding due to poetical job
loss, eliminate positions)
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Other Fact-Finding Techniques
● Document Review
Fax, hard copies
● Observation
– Seeing the system in action gives you
additional perspective and a better
understanding of the system procedures
– Plan you observations in advance
– Hawthorne Effect: productivity improved
when workers being observed.
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Other Fact-Finding Techniques
● Questionnaires and Surveys
– 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
Sample questionnaires on p. 113, Fig. 321
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Other Fact-Finding Techniques
● Questionnaires and Surveys
– 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
● Questionnaires and Surveys
– 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
● Sampling: collect examples of
documents
Fact: list of 100 complains errors in
statement
– Systematic sample (select every 20th
customer for review)
– Stratified sample (select 5 from each of
the 4 different zip code areas)
– Random sample (select any 20
customers)
– Main objective of a sample is to ensure
that it represents the overall population49
Other Fact-Finding Techniques
● Research
– Newsgroups
– Site visit
Figure 3-23
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Other Fact-Finding Techniques
● Interviews vs. Questionnaires
– 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
suggestions
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Documentation
● The Need for Recording the Facts
– 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
● Software Tools
– CASE tools
– Word
processing
– Spreadsheets
– Databases
Figure 3-24
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Documentation
● Software Tools
– Presentation graphics
– Personal information managers
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Preview of Enterprise Modeling (Ch.
4)
● 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
● The systems analysis phase includes three
activities: requirements modeling, enterprise
modeling (Ch.4), and development strategies(Ch.5)
● Req. modeling identifies requirements for input,
output, processes, performances and controls.
● Main objective: to understand the proposed project
and build a solid foundation for the systems design
phase
● JAD, a team-based, fact-finding approach for Req.
modeling
● RAD, a complete method for speed-up info.
development
with 4 phases: req. planning, user design,
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construction, and cutover.
Chapter Summary
● Tools to model sys. requirements: FDD, UML, case
diagrams, and sequence diagrams
● The fact-finding process includes interviewing,
document review, observation, questionnaires,
sampling, and research
● Systems analysts should carefully record and
document factual information as it is collected.
Documents should be through, specific, well presented
(written English, charts, graphs, tables). Various
software tools can help you visualize and describe an
information system professionally.
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