phase 2: systems analysis chapter 3 requirements modeling

Phase 2: Systems Analysis

Chapter 3

Requirements Modeling

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

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

Systems Analysis Phase Overview

• Systems Analysis Skills– Analytical skills– Interpersonal skills

• Team-Oriented Methods and Techniques– Joint application development (JAD)– Rapid application development (RAD)

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

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

Modeling Tools and Techniques

– Sequence diagrams• Shows timing of transactions between objects as

they occur

Figure 3-13

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

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

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

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

System Requirements Checklist

• Performance– The system must support 25 users online

simultaneously– Response time must not exceed four seconds

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

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

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

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

Interviews

• Systems analysts spend a great deal of time talking with people

• Much of that time is spent conducting interviews

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

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

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

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

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

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

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

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

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

Other Fact-Finding Techniques

• Research– Newsgroups– Site visit

Figure 3-23

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

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

Documentation

• Software Tools– CASE Tools– Word processing– Spreadsheets

• Histogram

– Databases

Figure 3-24

Documentation

• Software Tools– Presentation graphics– Personal information managers

• Personal information manager (PIM)• Handheld computers• Personal digital assistants (PDAs)

Figure 3-25

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

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

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

Test Yourself

2. The end product of the systems analysis phase is a system requirements document (T/F).

Test Yourself

2. The end product of the systems analysis phase is a system requirements document (T/F).

True

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).

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

Test Yourself

4. Name two of the five general categories of system requirements:

Test Yourself

4. Name two of the five general categories of system requirements:

1. outputs

2. inputs

3. processes

4. performance

5. controls

Test Yourself

5. The fact-finding process includes interviewing, __________, observation, questionnaires, sampling, and _______.

Test Yourself

5. The fact-finding process includes interviewing, document review, observation, questionnaires, sampling, and research.

Test Yourself

6. What are the seven basic steps for interviewing?

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

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?”

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?”

Test Yourself

8. There are many other fact-finding techniques, in addition to interviewing. Name at least two others.

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.

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?

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.

Test Yourself

10. Name at least two guidelines for good documentation.

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

End Chapter 3