McGraw-Hill/Irwin Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved. Chapter 4 Systems Requirements Determination

4-2 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

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

4-4 Developing an Analysis Strategy Process-oriented approach Object-oriented approach

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.

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.

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++.

4-8 The Three “I”s of Requirements Determination Impertinence Impartially Insight

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

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

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

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

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

4-14 Requirements Determination Deliverables Good Requirement Characteristics –Testable and Verifiable –Justifiable –Unambiguous –Consistent –Modifiable –Hierarchically Traceable

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

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

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

4-18 Requirements Determination Methods Directive Interview Questionnaires and Surveys Direct Observation Archival Document Analysis Forms Analysis

4-19 Table 4-4. Traditional Information Gathering Methods

4-20 Direct Interview Structured Interview –Analysts determine the structure of the interview Unstructured Interview –Respondent provides the structure for the conversation

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

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

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

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

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.

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

4-27 Questionnaires and Surveys Easy to prepare Less expensive Allow analysts to gather more information

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

4-29 Figure 4-1. Example of Typical Questionnaire

4-30 Questionnaires and Surveys Survey Design –Validity –Reliability –Ease of use

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.

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)

4-33 Questionnaires and Survey Ease of use –Respondents should find the questionnaire understandable and easily completed in a reasonable amount of time

4-34ScalingScaling 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

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

4-36 Table Guidelines for Choosing the Most Appropriate Scaling Method

4-37SamplingSampling 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.

4-38 Types of Samples Convenience sample Purposive sample Random sample Stratified sample

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

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

4-41 External Research –Computer trade journals –Technical reference manuals –Industry trade associations –Published case studies –Internet (WWW)

4-42 Figure 4-3. Example of a Business Form

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

4-44 Joint Application Development JAD Participants –Session leader –User –Manager –Project sponsor –Analyst –Scribe –IS staff

4-45 Table Roles and Responsibilities of Typical JAD Participants

4-46 Figure 4-4. MicroTouch, Inc., IBID Electronic Whiteboard

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.

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

4-49 Table Review of Requirements Gathering Approaches

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.

McGraw-Hill/Irwin Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved. Chapter 4 End of Chapter