phase 2: systems analysis chapter 3 requirements modeling
TRANSCRIPT
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Phase 2: Systems Analysis
Chapter 3
Requirements Modeling
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Phase Description
• 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, you will consider system development strategies
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Systems Analysis Phase Overview
• Uses models and other documentation tools to visualize and describe the proposed system
• The deliverable is a system requirements document
Figure 3-2 Systems
RequirementsDocument
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Systems Analysis Phase Overview
• Systems Analysis Skills– Analytical skills– Interpersonal skills
• Team-Oriented Methods and Techniques– Joint application development (JAD)– Rapid application development (RAD)
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Modeling Tools and Techniques
• CASE Tools– Offer powerful modeling features– System analysts use modeling and fact-
finding interactively
• Functional Decomposition Diagrams– Functional decomposition diagram (FDD)
Figure 3-9
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Modeling Tools and Techniques
• Unified Modeling Language - Provides various graphical tools and techniques to represent the IS from user’s perspective– Use case diagrams
Figure 3-10
Figure 3-12
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Modeling Tools and Techniques
– Sequence diagrams• Shows timing of transactions between objects as
they occur
Figure 3-13
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System Requirements Checklist
• System requirement – a feature that must be added to the IS to satisfy business requirements
• Five general categories– Outputs– Inputs– Processes– Performance– Controls
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System Requirements Checklist
• Outputs– The Web site must report online volume
statistics every four hours, and hourly during peak periods
– The inventory system must produce a daily report showing the part number, description, quantity on hand, quantity allocated, quantity available, and unit cost of all parts — sorted by part number
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System Requirements Checklist
• Inputs– Manufacturing employees must swipe their ID
cards into online data collection terminals that record labor costs and calculate production efficiency
– The department head must enter overtime hours on a separate screen
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System Requirements Checklist
• Processes– The student records system must allow record
access by either the student name or the student number
– As the final step in year-end processing, the payroll system must update employee salaries, bonuses, and benefits and produce tax data required by the IRS
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System Requirements Checklist
• Performance– The system must support 25 users online
simultaneously– Response time must not exceed four seconds
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System Requirements Checklist
• Controls– The system must provide log-on security at
the operating system level and at the application level
– An employee record must be added, changed, or deleted only by a member of the human resources department
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Future Growth, Costs, and Benefits
• Scalability– Determines how a system will determine
future growth and demands.– 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– Direct + indirect costs– especially important if the development team
is evaluating several alternatives– Rapid Economic Justification (REJ)
• Microsoft’s method for measuring TCO and benefits
Figure 3-14
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Fact-Finding
• Overview– The first step is to identify the information you
need– Start with a fact-finding plan
• Who, What, Where, When, How, and Why?– Difference between asking what is being done
and what could or should be done
Figure 3-15
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Interviews
• Systems analysts spend a great deal of time talking with people
• Much of that time is spent conducting interviews
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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
Figure 3-17
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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– Close-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
Figure 3-18
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
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Other Fact-Finding Techniques
• Document Review
• Observation– Seeing the system in action gives you
additional perspective and a better understanding of the system procedures
– Plan your observations in advance– Hawthorne Effect
Figure 3-20
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Other Fact-Finding Techniques
• Questionnaires and Surveys– When designing a questionnaire, the most
important rule of all is to make sure that your questions collect the right data in a form that you can use to further your fact-finding
– Fill-in form
Figure 3-21
Figure 3-22
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Other Fact-Finding Techniques
• Sampling– Systematic sample– Stratified sample– Random sample– Main objective of a sample is to ensure that it
represents the overall population accurately
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Other Fact-Finding Techniques
• Research– Newsgroups– Site visit
Figure 3-23
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Other Fact-Finding Techniques
• Interviews versus Questionnaires– Interview is more familiar and personal– If you require detailed information from only a
few people, then you probably should interview each person
– When you seek input from a large group questionnaire is a very useful tool
– 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
• Histogram
– Databases
Figure 3-24
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Documentation
• Software Tools– Presentation graphics– Personal information managers
• Personal information manager (PIM)• Handheld computers• Personal digital assistants (PDAs)
Figure 3-25
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Preview of Enterprise Modeling
• 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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Test Yourself
1. Match the terms in the left column to the proper definitions in the right column.
1. Functionaldecompositiondiagram
2. Use case diagram
3. Sequencediagram
a. Shows the timing of transactions between objects as they occur
b. Visual representation of the interaction between users and the information system
c. Top-down representation of business functions and processes
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Test Yourself
1. Match the terms in the left column to the proper definitions in the right column.
1. Functionaldecompositiondiagram
2. Use case diagram
3. Sequencediagram
a. Shows the timing of transactions between objects as they occur
b. Visual representation of the interaction between users and the information system
c. Top-down representation of business functions and processes
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Test Yourself
2. The end product of the systems analysis phase is a system requirements document (T/F).
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Test Yourself
2. The end product of the systems analysis phase is a system requirements document (T/F).
True
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Test Yourself
3. Rapid application development (RAD) is a team-based technique that speeds up information systems development but doesn’t produce a functioning system like JAD does (T/F).
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Test Yourself
3. Rapid application development (RAD) is a team-based technique that speeds up information systems development but doesn’t produce a functioning system like JAD does (T/F).
False
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Test Yourself
4. Name two of the five general categories of system requirements:
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Test Yourself
4. Name two of the five general categories of system requirements:
1. outputs
2. inputs
3. processes
4. performance
5. controls
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Test Yourself
5. The fact-finding process includes interviewing, __________, observation, questionnaires, sampling, and _______.
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Test Yourself
5. The fact-finding process includes interviewing, document review, observation, questionnaires, sampling, and research.
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Test Yourself
6. What are the seven basic steps for interviewing?
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Test Yourself
6. What are the seven basic steps for interviewing?1. Determine the people to interview
2. Establish objectives for the interview
3. Develop interview questions
4. Prepare for the interview
5. Conduct the interview
6. Document the interview
7. Evaluate the interview
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Test Yourself
7. The following question is an example of an open-ended/closed-ended interview question:“What added features would you like to have in
the new system?”
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Test Yourself
7. The following question is an example of an open-ended/closed-ended interview question:“What added features would you like to have in
the new system?”
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Test Yourself
8. There are many other fact-finding techniques, in addition to interviewing. Name at least two others.
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Test Yourself
8. There are many other fact-finding techniques, in addition to interviewing. Name at least two others.
Document review, observation, surveys and questionnaires, sampling, and research.
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Test Yourself
9. What is sampling? If you have a list of customers, and want to methodically select every 10th customer for review, which sampling technique would you use?
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Test Yourself
9. What is sampling? If you have a list of customers, and want to methodically select every 10th customer for review, which sampling technique would you use?
Sampling is a technique where the analyst collects examples of actual documents, records, logs, or forms.
A systemic sample would select every 10th customer.
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Test Yourself
10. Name at least two guidelines for good documentation.
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Test Yourself
10. Name at least two guidelines for good documentation.
1. Write it down2. Record information as soon as possible3. Use the simplest recording method4. Ensure that your work is understandable5. Organize your documentation material
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End Chapter 3