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Chapter 4

Chapter 4. Systems Requirements Determination. Learning Objectives. Understand the three types of system requirements Understand the selection criteria for an analysis strategy Learn the three “I”’s of requirements determination. Learning Objectives.

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Chapter 4

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  1. Chapter 4 Systems Requirements Determination

  2. Learning Objectives • Understand the three types of system requirements • Understand the selection criteria for an analysis strategy • Learn the three “I”’s of requirements determination SAD/CHAPTER 4

  3. Learning Objectives • Understand the four common mistakes made during requirements determination • Identify and understand the characteristics of a good requirement • Understand the characteristics and application of both the traditional and modern information-gathering approaches SAD/CHAPTER 4

  4. Developing an Analysis Strategy • Process-oriented approach • Object-oriented approach SAD/CHAPTER 4

  5. Types of System Requirements • Functional Requirements • Describe the various interactions between the system and its environment • Example: The system must display the local time based on the location of the workstation. SAD/CHAPTER 4

  6. Types of System Requirements • Nonfunctional Requirement • Describe the aspects of the system not related to the specific functional behavior of the system • Example: The response time for all requests must be less than 1 second. SAD/CHAPTER 4

  7. Types of System Requirements • Constraints • Requirements imposed on the system by the client or the system environment • Example: The system language must be C++. SAD/CHAPTER 4

  8. The Three “I”s of Requirements Determination • Impertinence • Impartially • Insight SAD/CHAPTER 4

  9. The Three “I”s of Requirements Determination • Impertinence • Analysts should question everything and take nothing for granted during requirements determination. SAD/CHAPTER 4

  10. The Three “I”s of Requirements Determination • Impartially • Analysts must maintain a posture of complete impartiality when gathering user requirements. SAD/CHAPTER 4

  11. The Three “I”s of Requirements Determination • Insight • Analysts must assume that anything is possible. • Constant attention to detail • Creative thinking SAD/CHAPTER 4

  12. The Four Common Mistakes in Requirements Determination 1. Assuming a Functional System • End users’ lack of cross-functional perspective 2. Collecting Requirements from End User instead of All End Users • Gather requirements from groups rather than individuals SAD/CHAPTER 4

  13. The Four Common Mistakes in Requirements Determination 3. Asking the Wrong Question • End users often try to provide right answers for any question 4. Failing to Allow Refinement through Trial and Error • Experiential learning SAD/CHAPTER 4

  14. Requirements Determination Deliverables • Good Requirement Characteristics • Testable and Verifiable • Justifiable • Unambiguous • Consistent • Modifiable • Hierarchically Traceable SAD/CHAPTER 4

  15. Table 4-1. Examples of Information Gathered During Requirements Determination SAD/CHAPTER 4

  16. Table 4-2. Characteristics of a Well-Stated System Requirement SAD/CHAPTER 4

  17.  Table 4-3. Examples of Testable and Nontestable Requirements SAD/CHAPTER 4

  18. Requirements Determination Methods • Directive Interview • Questionnaires and Surveys • Direct Observation • Archival Document Analysis • Forms Analysis SAD/CHAPTER 4

  19. Table 4-4. Traditional Information Gathering Methods SAD/CHAPTER 4

  20. Direct Interview • Structured Interview • Analysts determine the structure of the interview • Unstructured Interview • Respondent provides the structure for the conversation SAD/CHAPTER 4

  21. Table 4-5. Comparative Advantages and Disadvantages of the Direct Interview Method SAD/CHAPTER 4

  22. Table 4-6. Characteristics of Structured and Unstructured Interviews SAD/CHAPTER 4

  23. Direct Interview • Question Types • Open-ended question • Allow the respondent to answer the question in any way he or she deems appropriate • Closed-ended question • Limit the respondent to a finite set of answers • Bipolar question SAD/CHAPTER 4

  24. Table 4-7. Comparative Advantages and Disadvantages of Open- and Closed-Ended Question Types SAD/CHAPTER 4

  25. Managing the Interview Process • Do not phrase questions in a way that imply a right or wrong answer. • Remember to listen, listen, and listen some more. • Schedule interviews with a variety of users. • Do not set expectations about possible new function and features. • After the interview, prepare notes within 48 hours. SAD/CHAPTER 4

  26. Focus Groups • Effective use of everyone’s time. • Discover and resolve inconsistent perspectives among respondents. • Observe the interaction between respondents. SAD/CHAPTER 4

  27. Questionnaires and Surveys • Easy to prepare • Less expensive • Allow analysts to gather more information SAD/CHAPTER 4

  28. Table 4-8. Comparative Advantages and Disadvantages of the Questionnaire Method SAD/CHAPTER 4

  29. Figure 4-1. Example of Typical Questionnaire SAD/CHAPTER 4

  30. Questionnaires and Surveys • Survey Design • Validity • Reliability • Ease of use SAD/CHAPTER 4

  31. Questionnaires and Surveys • Validity • Information obtained by questionnaires is done so in an accurate and interpretable manner. • Use pilot tests to revise the content and improve the flow of the questionnaire . SAD/CHAPTER 4

  32. Questionnaires and Surveys • External Reliability • A measure of the consistency of results obtained across multiple administrations • Internal reliability • The degree of consistency associated with the responses obtained (include more than one question on a key issue) SAD/CHAPTER 4

  33. Questionnaires and Survey • Ease of use • Respondents should find the questionnaire understandable and easily completed in a reasonable amount of time SAD/CHAPTER 4

  34. Scaling • Scaling: The process used to assign some value or symbol to a particular characteristics such that it can be measured and evaluated. • Nominal • Ordinal • Interval • Ratio SAD/CHAPTER 4

  35. Table 4-9. Examples of Different Questionnaire Scaling Methods SAD/CHAPTER 4

  36. Table 4-10. Guidelines for Choosing the Most Appropriate Scaling Method SAD/CHAPTER 4

  37. Sampling • A systematic process to select representative members of a population. • Decide on the scope of the data. • Identify the population of interest. • Determine sample characteristics. • Calculate the minimum acceptance sample size. SAD/CHAPTER 4

  38. Types of Samples • Convenience sample • Purposive sample • Random sample • Stratified sample SAD/CHAPTER 4

  39. Direct Observation • Does not require the respondent to verbalizing or recall the past • More objective measure of the true nature of an event or activity • Consider the Hawthorne Effect SAD/CHAPTER 4

  40. Document Analysis • Organizational Documents • Mission Statement • Organizational Chart • Job Description • Financials • Policies and Procedures • Current System Documentation • Form Analysis (Figure 4-3) SAD/CHAPTER 4

  41. External Research • External Research • Computer trade journals • Technical reference manuals • Industry trade associations • Published case studies • Internet (WWW) SAD/CHAPTER 4

  42. Figure 4-3. Example of a Business Form SAD/CHAPTER 4

  43. Modern Methods for Requirements Determination • Joint Application Development (JAD) • Bring together the key stakeholders to facilitate the determination of requirements • Promote a sense of common ownership • Reduce the time in gathering vital information • Identify discrepancies and facilitate the resolution of conflict information and requirements SAD/CHAPTER 4

  44. Joint Application Development • JAD Participants • Session leader • User • Manager • Project sponsor • Analyst • Scribe • IS staff SAD/CHAPTER 4

  45. Table 4-12. Roles and Responsibilities of Typical JAD Participants SAD/CHAPTER 4

  46. Figure 4-4. MicroTouch, Inc., IBID Electronic Whiteboard SAD/CHAPTER 4

  47. Iterative Prototyping • Quickly convert the basic requirements into a limited working model • The working model is modified to reflect the feedback and information generated by the end users. SAD/CHAPTER 4

  48. Iterative Prototyping • Expedite the necessary changes very early in the development process • Prototypes are only representations of the final system and should never be considered for implementation SAD/CHAPTER 4

  49. Table 4-13. Review of Requirements Gathering Approaches SAD/CHAPTER 4

  50. Chapter Summary • The need for skilled systems analysts who understand how to analyze complex business problems and gather information in an accurate and structured manner will continue to be high. SAD/CHAPTER 4

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