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Determining System Requirements Classes 9,10
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SDLC Project Identification & Selection Project Initiation & Planning Analysis ** Logical Design Physical Design Implementation Maintenance
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Requirements Determination System requirements Functional requirements Current and future functions Current and future data Current and future employee jobs
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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
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Remember to...
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Who will you get info from? User Stakeholders Users Managers Client Stakeholders Technical Stakeholders
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What Information Do You Need? 1. 2. 3.
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Traditional Methods for Determining System Requirements Administering questionnaires Interviewing and listening Interviewing groups Directly observing users Analyzing procedures & other documents
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Administering Questionnaires Advantages & Disadvantages Strengths 1. 2. 3. Weaknesses 1. 2. 3.
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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
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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
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Interviewing & Listening Before During the interview Afterwards
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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
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Interviews Advantages & Disadvantages 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
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How do you choose interview questions? Open-ended questions 1. 2. 3. Closed-ended questions 1. 2. 3.
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Find out about someone’s job 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
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Interviewing Groups Adv & Disadv 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
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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
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Directly Observing Users Strengths Doesn’t rely on a user’s memory More objective and accurate than interviews Weaknesses Hawthorne effect Time consuming
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Temporary Job Assignment 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
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Reviewing internal documents 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
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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
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Structured Walkthroughs What is it? When is it done? Who is involved? How is it done?
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