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Chapter 4. Investigating and Determining System Requirements. Performing Requirements Determination. Gather information on what system should do from many sources Users Reports Forms Procedures. 6. 2. Performing Requirements Determination. Characteristics for gathering requirements - PowerPoint PPT Presentation
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Chapter 4
Investigating and Determining System Requirements
Performing Requirements Determination
Gather information on what system should do from many sources Users Reports Forms Procedures
6.26.2
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
6.36.3
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
6.46.4
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
6.56.5
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
6.66.6
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
6.76.7
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
6.86.8
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
6.96.9
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
6.106.10
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
system6.116.11
Joint Application Design (JAD)
Participants Session Leader Users Managers Sponsor Systems Analysts Scribe IS Staff
6.126.12
Joint Application Design (JAD)
End Result Documentation detailing existing system Features of proposed system
6.136.13
PrototypingQuickly converts requirements to working version of systemOnce the user sees requirements converted to system, will ask for modifications or will generate additional requestsMost 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
6.146.14
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
6.156.15
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
6.166.16
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
6.176.17
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
6.186.18
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
6.196.19
Summary
Other means of gather requirements Observing workers Analyzing business documents
Joint Application Design (JAD)
Prototyping
Business Process Reengineering (BPR) Disruptive technologies
6.206.20
Requirements Discovery (Continued)
Selecting the Best Alternative Design Strategy
6.236.23
Learning Objectives
Describe different sources of softwareLearn to assemble the various pieces of
an alternative design strategyLearn how to generate at least three
alternative design strategiesDiscuss selecting the best design
strategy using both qualitative and quantitative methods
6.246.24
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
6.236.23
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
6.246.24
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
6.256.25
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
6.266.26
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
6.276.27
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
6.286.28
Issues to Consider in Generating Alternatives
Sources of Software Hardware manufacturers Packaged software producers Custom software producers Enterprise solution software In-house development
6.296.29
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
6.306.30
Criteria for Choosing Off-the-Shelf Software
Flexibility Ease of customization
Documentation User documentation Technical documentation
Response Time
Ease of Installation
6.316.31
Validating Purchased Software Information
Information from vendor
Software evaluation period
Customer references from vendor
Independent software testing service
Trade publications
6.326.32
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
6.336.33
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
6.346.34
Implementation Issues
Technical and social aspects of implementation need to be addressed
Training
Disruption of work
6.356.35
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
6.366.36
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
6.376.37
