Determining System
Requirements
Classes 9,10

SDLC
Project Identification
& Selection
Project Initiation
& Planning
Analysis
**
Logical Design
Physical Design
Implementation
Maintenance

Requirements Determination
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System requirements
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Functional requirements
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Current and future functions
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Current and future data
Current and future employee jobs

Requirements Structuring
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Two essential views of the current and replacement information systems. Both are describing the same system, but in a different way.
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Process view: The sequence of data movement & handling operations within the system
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Data flow diagrams
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Data: The inherent structure of data independent of how or when it is processed
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Entity-relation diagrams

Remember to...

Who will you get info from?
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User Stakeholders
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Users
Managers
Client Stakeholders
Technical Stakeholders

What Information Do You
Need?
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1.
2.
3.

Traditional Methods for
Determining System Requirements
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Administering questionnaires
Interviewing and listening
Interviewing groups
Directly observing users
Analyzing procedures & other documents

Administering Questionnaires
Advantages & Disadvantages
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Strengths
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1.
2.
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3.
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Weaknesses
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1.
2.
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3.

Give Me Ambiguity or Give Me
Something Else!
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How often do you back up your computer files?
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A. Frequently
B. Sometimes
C. Hardly at all
D. Never

This is better…

How often do you back up the computer files stored on the hard disk on the PC you use for over 50% of your work time?
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A. Frequently (at least once per week)
B. Sometimes (from 1 to 3 times per month)
C. Hardly at all (once per month or less)
D. Never

Interviewing & Listening
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
Before
During the interview
Afterwards

During the Interview

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Beginning
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Introduction, open-ended questions, interest & attention
Middle
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Open & close-ended questions, f-u questions, active listening, provide feedback, limit notetaking
End
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Summarize, request feedback and/or f-u, ask for corrections

Interviews
Advantages & Disadvantages
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Strengths
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Extracts both qualitative and quantitative data

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Detailed and summary data
Good way to find needs and assumptions

Weaknesses
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Requires skills
May be biased; May collect lots of useless data

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Expensive, time consuming
Requires other methods to verify results

How do you choose interview questions?
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Open-ended questions
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1.
2.
3.
Closed-ended questions
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1.
2.
3.

Find out about someone’s job
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Write 3 open-ended questions
Ask 3 open-ended questions (You may substitute questions during interview.)
Write down answers
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Write 3 closed-ended questions
Ask 3 closed-ended questions (You may substitute questions during interview.)
Write down answers

Interviewing Groups
Adv & Disadv
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Strengths
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Not biased by one user’s opinion
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Can get many user’s opinion
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Weaknesses
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With many people present, decisionmaking takes time
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Interruptions during process

You May Need to Analyze
Work Procedures
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Work procedures describe a particular job or task
May show duplication of effort
May find missing steps
May contradict info collected from interviews, questionnaires, and observations
Formal systems vs informal systems

Directly Observing
Users

Strengths

Doesn’t rely on a user’s memory
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More objective and accurate than interviews
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Weaknesses
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Hawthorne effect
Time consuming

Temporary Job Assignment
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Strengths
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Good for learning context, terminology, procedures
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Provides insight for other questions
Get operation “feel”; adds to analysts credibility with users
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Weaknesses
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Time Consuming
May bias future work design towards way things are currently done

Reviewing internal documents
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Strengths
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Good way to learn history and politics
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Explains current context
May help understand why and way of current procedures & applications
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Weaknesses
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May bias future work design
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Not useful for obtaining current attitudes or motives

Modern Methods for Determining
System Requirements
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Prototyping
Joint Application Design (JAD) - Intensive meetings between users, managers, sponsor,
& systems analysts to discuss & review system requirements
Group Support Systems (GSS) to share ideas
& voice opinions
BPR – Business process reengineering
CASE tools to analyze existing systems

Structured Walkthroughs
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What is it?
When is it done?
Who is involved?
How is it done?