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Chapter 4 Investigating and Determining System Requirements.

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Presentation on theme: "Chapter 4 Investigating and Determining System Requirements."— Presentation transcript:

1 Chapter 4 Investigating and Determining System Requirements

2 Performing Requirements Determination Gather information on what system should do from many sources Users Reports Forms Procedures 6.2

3 Performing Requirements Determination Characteristics for gathering requirements Impertinence  Question everything Impartiality  Find the best organizational solution Relaxation of constraints Attention to detail Reframing  View the organization in new ways 6.3

4 Deliverables and Outcomes Types of deliverables: Information collected from users Existing documents and files Computer-based information Understanding of organizational components  Business objective  Information needs  Rules of data processing  Key events 6.4

5 Traditional Methods for Determining Requirements Interviewing and Listening Gather facts, opinions and speculations Observe body language and emotions Guidelines  Plan Checklist Appointment  Be neutral  Listen  Seek a diverse view 6.5

6 Traditional Methods for Determining Requirements Interviewing (Continued) Interview Questions  Open-Ended No pre-specified answers  Close-Ended Respondent is asked to choose from a set of specified responses 6.6

7 Traditional Methods for Determining Requirements Administering Questionnaires More cost-effective than interviews Choosing respondents  Should be representative of all users  Types of samples Convenient Random sample Purposeful sample Stratified sample 6.7

8 Traditional Methods for Determining Requirements Questionnaires Design  Mostly closed-ended questions  Can be administered over the phone or in person Vs. Interviews  Interviews cost more but yield more information  Questionnaires are more cost-effective  See table 4-4 for a complete comparison 6.8

9 Traditional Methods for Determining Requirements Directly Observing Users Serves as a good method to supplement interviews Often difficult to obtain unbiased data  People often work differently when being observed 6.9

10 Analyzing Procedures and Other Documents Types of information to be discovered: Problems with existing system Opportunity to meet new need Organizational direction Names of key individuals Values of organization Special information processing circumstances Rules for processing data 6.10

11 Modern Methods for Determining Requirements Joint Application Design (JAD) Brings together key users, managers and systems analysts Purpose: collect system requirements simultaneously from key people Conducted off-site Prototyping Repetitive process Rudimentary version of system is built Replaces or augments SDLC Goal: to develop concrete specifications for ultimate system 6.11

12 Joint Application Design (JAD) Participants Session Leader Users Managers Sponsor Systems Analysts Scribe IS Staff 6.12

13 Joint Application Design (JAD) End Result Documentation detailing existing system Features of proposed system 6.13

14 Prototyping Quickly converts requirements to working version of system Once the user sees requirements converted to system, will ask for modifications or will generate additional requests Most useful when: User requests are not clear Few users are involved in the system Designs are complex and require concrete form History of communication problems between analysts and users Tools are readily available to build prototype 6.14

15 Prototyping Drawbacks Tendency to avoid formal documentation Difficult to adapt to more general user audience Sharing data with other systems is often not considered Systems Development Life Cycle (SDLC) checks are often bypassed 6.15

16 Business Process Reengineering (BPR) Search for and implementation of radical change in business processes to achieve breakthrough improvements in products and services Goals Reorganize complete flow of data in major sections of an organization Eliminate unnecessary steps 6.16

17 Business Process Reengineering (BPR) Goals (Continued) Combine steps Become more responsive to future change Identification of processes to reengineer Key business processes  Set of activities designed to produce specific output for a particular customer or market  Focused on customers and outcome  Same techniques are used as were used for requirements determination 6.17

18 Business Process Reengineering (BPR) Identify specific activities that can be improved through BPR Disruptive technologies Technologies that enable the breaking of long-held business rules that inhibit organizations from making radical business changes 6.18

19 Summary Interviews Open-ended and close-ended questions Preparation is key Questionnaires Must be carefully designed Can contain close-ended as well as open- ended questions 6.19

20 Summary Other means of gather requirements Observing workers Analyzing business documents Joint Application Design (JAD) Prototyping Business Process Reengineering (BPR) Disruptive technologies 6.20

21 Requirements Discovery (Continued) Selecting the Best Alternative Design Strategy 6.23

22 Learning Objectives Describe different sources of software Learn to assemble the various pieces of an alternative design strategy Learn how to generate at least three alternative design strategies Discuss selecting the best design strategy using both qualitative and quantitative methods 6.24

23 Learning Objectives Learn how to use the results of the analysis phase to update a Baseline Project Plan (BPP) Discuss design strategies and how they are applied to the Internet 6.23

24 Selecting the Best Alternative Design Strategy Two basic steps Generate a comprehensive set of alternative design strategies Select the one design strategy that is most likely to result in the desired information system Process Divide requirements into different sets of capabilities Enumerate different potential implementation environments that could be used to deliver the different sets of capabilities Propose different ways to source or acquire the various sets of capabilities for the different implementation environments 6.24

25 Selecting the Best Alternative Design Strategy Deliverables At least three substantially different system design strategies for building the replacement information system A design strategy judged most likely to lead to the most desirable information system A Baseline Project Plan (BPP) for turning the most likely design strategy into a working information system 6.25

26 Generating Alternative Design Strategies Best to generate three alternatives Low-end  Provides all required functionality users demand with a system that is minimally different from the current system High-end  Solves problem in question and provides many extra features users desire Midrange  Compromise of features of high-end alternative with frugality of low-end alternative 6.26

27 Drawing Bounds on Alternative Designs Minimum Requirements Mandatory features versus desired features Forms of features  Data  Outputs  Analyses  User expectations on accessibility,response time and turnaround time Constraints on System Development Time Financial Legal Dynamics of the problem 6.27

28 Issues to Consider in Generating Alternatives Outsourcing The practice of turning over responsibility of some to all of an organization ’ s information systems applications and operations to an outside firm Can provide a cost effective solution 6.28

29 Issues to Consider in Generating Alternatives Sources of Software Hardware manufacturers Packaged software producers Custom software producers Enterprise solution software In-house development 6.29

30 Criteria for Choosing Off-the-Shelf Software Cost In-house versus purchased Functionality Mandatory, essential and desired features Vendor Support Installation Training Technical Support Viability of Vendor 6.30

31 Criteria for Choosing Off-the-Shelf Software Flexibility Ease of customization Documentation User documentation Technical documentation Response Time Ease of Installation 6.31

32 Validating Purchased Software Information Information from vendor Software evaluation period Customer references from vendor Independent software testing service Trade publications 6.32

33 Hardware and Software Issues Existing Platform Lower costs Information system staff is familiar with operation and maintenance Increased odds of successfully integrating system with existing applications No added costs of converting old systems to new platform or transferring data New Hardware and System Software Some software components will only run on new platform Developing system for new platform gives organization opportunity to upgrade technology holdings New requirements may allow organization to radically change its computing operations 6.33

34 Hardware and Software Issues Request for Proposal (RFP) A document provided to vendors to ask them to propose hardware and system software that will meet the requirements of your new system 6.34

35 Implementation Issues Technical and social aspects of implementation need to be addressed Training Disruption of work 6.35

36 Internet Development: Selecting the Best Alternative Design Strategy Proposed system is a scalable, three-tier approach  Scalable The ability to seamlessly upgrade the system through either hardware upgrades, software upgrades or both  Three-tier Web Server Provides connection to the Internet and presentation of HTML page Applications Server Middle layer of software and hardware that lies between Webserver and corporate network Corporate network Existing organizational computing infrastructure 6.36

37 Summary Sources of Software Identifying requirements and constraints Generating alternative design strategies Selecting the best design strategy Selecting the best design strategy for Internet applications 6.37


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