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Determining System Requirements

Determining System Requirements. Classes 9,10. SDLC. Project Identification & Selection. Project Initiation & Planning. Analysis **. Logical Design. Physical Design. Implementation. Maintenance. Requirements Determination. System requirements Functional requirements

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Determining System Requirements

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  1. Determining SystemRequirements Classes 9,10

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

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

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

  5. Remember to... Assume Anything is Possible Question Everything Pay Attention to Details Don't Jump to Conclusions Be Impartial

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

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

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

  9. Strengths 1. 2. 3. Weaknesses 1. 2. 3. Administering QuestionnairesAdvantages & Disadvantages

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

  11. 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? • 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

  12. Interviewing & Listening • Before • During the interview • Afterwards

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

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

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

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

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

  18. You May Need to Analyze Work Procedures • 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

  19. Strengths Doesn’t rely on a user’s memory More objective and accurate than interviews Weaknesses Hawthorne effect Time consuming Directly ObservingUsers

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

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

  22. Modern Methods for Determining System Requirements • 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

  23. Structured Walkthroughs • What is it? • When is it done? • Who is involved? • How is it done?

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