Saturday, November 17, 2007

Systems Analysis & Design - Determining System Requirements

Determining System Requirements

Learning Objectives
  • Describe options for designing and conducting interviews and develop a plan for conducting an interview to determine system requirements.
  • Design, distribute, and analyze questionnaires to determine system requirements.
  • Explain advantages and pitfalls of observing workers and analyzing business documents to determine requirements.
  • Explain how computing can provide support for requirements determination.
  • Learn about Joint Application Design (JAD)
  • Use prototyping during requirements determination.
  • Select the appropriate methods to elicit system requirements.
  • Apply requirements determination to Internet applications.

  • Performing Requirements Determination
  • Gather information on what system should do from many sources.
  • Users
  • Characteristics for gathering requirements
  • -Impertinence
    -Question everything
    -Find the best organizational solution
    -Relaxation of constraints
    -Attention to detail
    -Reframing - View the organization in new ways

    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

    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
    • Interviewing (Continued)
      • Interview Questions
        • Open-Ended
          • No pre-specified answers
        • Close-Ended
          • Respondent is asked to choose from a set of specified responses
    • Additional Guidelines
      • Do not phrase questions in ways that imply a wrong or right answer
      • Listen very carefully to what is being said
      • Type up notes within 48 hours
      • Do not set expectations about the new system
    • 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
    • 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 7-4 for a complete comparison
    • Interviewing Groups
      • Advantages
        • More effective use of time
        • Enables people to hear opinions of others and to agree or disagree
      • Disadvantages
        • Difficulty in scheduling
      • Nominal Group Technique
        • Facilitated process to support idea generation by groups
        • Individuals work alone to generate ideas which are pooled under guidance of a trained facilitator
    • Directly Observing Users
      • Serves as a good method to supplement interviews
      • Often difficult to obtain unbiased data
        • People often work differently when being observed

    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
      • Reasons for current system design
      • Rules for processing data
    • Four types of useful documents
      • Written work procedures
        • Describes how a job is performed
        • Includes data and information used and created in the process of performing the job or task
        • Business form
          • Explicitly indicate data flow in or out of a system.
        • Report
          • Enables the analyst to work backwards from the report to the data that generated it
        • Description of current information system

    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

  • Joint Application Design (JAD)
    -Session Leader
    -Systems Analysts
    -IS Staff
    End Result
    -Documentation detailing existing system
    -Features of proposed system
    CASE Tools During JAD
    -Upper CASE tools are used
    -Enables analysts to enter system models directly into CASE during the JAD session
    -Screen designs and prototyping can be done during JAD and shown to users
    Supporting JAD with GSS
    -Group support systems (GSS) can be used to enable more participation by group members in JAD
    -Members type their answers into the computer
    -All members of the group see what other members have been typing

  • 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
  • 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

    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
      • 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
    • 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