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 Current and future functions Current and future data Current and future employee jobs

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

What Information Do You Need?

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

Administering Questionnaires Advantages & Disadvantages Strengths Weaknesses

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

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

Interviewing & Listening Before During the interview Afterwards

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

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

How do you choose interview questions? Open-ended questions Closed-ended questions

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

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

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

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

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

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

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

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