Modern Systems Analysis and Design Third Edition

1
Modern Systems Analysisand DesignThird Edition

• Chapter 7
• Determining System Requirements

7.1
2
Performing Requirements Determination

• System Analysis phase has three sub phases
• Requirements determination
• Requirements structuring
• Generating alternative design and selecting best
  one
• Gather information on what system should do from
  many sources
• Users
• Reports
• Forms
• Procedures

3
Performing Requirements Determination

• Characteristics for gathering requirements
• Impertinence
• Question everything
• Impartiality
• Find the best organizational solution
• Relaxation of constraints assuming anything is
  possible
• Attention to detail
• Reframing
• View the organization in new ways

7.3
4
Deliverables and Outcomes

• Types of deliverables
• Information collected from users
• interview transcripts, questionnaire responses,
  notes of observation
• Existing written information
• sample business forms and reports, procedure
  manuals, training manuals
• Computer-based information
• CASE repository contents and reports of
  existing system
• Understanding of organizational components
• Business objective
• Information people needs
• Data handled and when, how and who moves data
• Rules of data processing
• Key events

7.4
5
Traditional Methods for Determining Requirements

• Individually interview people who knows current
  system
• Survey people via questionnaires
• Interview group of people with different needs
• Observe workers at selected times to see how data
  is handled
• Study business documents
• Interviewing and Listening
• Guidelines for Effective Interviewing
• Prepare interviewee set up appointment time and
  duration convenient for interviewee
• Prepare checklist, agenda and questions to know
  the sequence and duration of questions to ask
• Listen carefully and take notes
• Review notes within 2 days of interview
• Be neutral and seek diverse views

7.5
6
Traditional Methods for Determining Requirements

• Choosing Interview Questions
• Open-Ended questions
• No pre-specified answers like what you think
  about ?
• Advantages give interviewees more sense of
  involvement put interviewee at ease as they
  respond in their own words
• Disadvantages takes long time to answer
  difficult to summarize
• Close-Ended questions
• Respondent is asked to choose from a set of
  specified responses
• Examples True or False, Multiple choice, rating
  a response
• Advantages takes less time to answer and more
  topics covered
• Disadvantages useful information may be
  overlooked
• Additional Guidelines
• Do not phrase questions in ways that imply a
  wrong or right answer
• Listen very carefully to what is being said
  take notes or record
• Type up notes within 48 hours
• Do not set expectations about the new system

7.6
7
Traditional Methods for Determining Requirements

• Administering Questionnaires
• Questionnaires Vs Interviews
• Interviews are very expensive and time-consuming
• Questionnaires are not expensive and can gather
  information from many people simultaneously in a
  relatively short time
• Interviews can have limited number of questions
  and limited number of people contacted
• Questionnaires give less depth of understanding
  as they provide no direct means to ask follow-up
  questions
• Interviews provide the opportunity to judge the
  truthfulness of responses by the words or voice
  tone or the body language of the respondent
• Questionnaires do not provide the opportunity to
  judge the accuracy of responses

7.7
8
Traditional Methods for Determining Requirements

• Choosing Questionnaire respondents if more
  people to survey decide which set of people to
  send questionnaire to or which questionnaire to
  send to which group of people
• Convenient people at a local site or willing to
  get surveyed
• Random sample select any person from a list
• Purposeful sample select people who satisfy
  certain criteria
• Stratified sample select random set from each of
  many categories
• Designing Questionnaires
• Questionnaires are most useful when used for
  specific purpose and not for general information
  gathering
• Questionnaires typically include closed-ended
  questions
• Questionnaires must be extremely clear in meaning
  and logical in sequence as any doubts cannot be
  cleared
• How often(?) do you backup your computer files
  (C or hard disk)?
• a) frequently b) sometimes c) hardly
  at all d) never

7.8
9
Traditional Methods for Determining Requirements

• Interviewing Groups interview several key
  people at once by several analysts, one asks
  questions other takes notes
• Advantages
• More effective use of time
• Enables people to hear opinions of others and to
  agree or disagree
• Disadvantages
• Difficulty in scheduling convenient time as many
  people are involved
• 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 which are then discussed and then
  number of ideas are reduced and carry forward
• Directly Observing Users
• People cannot always be trusted to reliably
  report their own actions
• Often difficult to obtain unbiased data
• People often work differently when being observed

7.9
10
Analyzing Procedures and Other Documents

• Types of information to be discovered in a
  document
• Problems with existing system
• Opportunity to meet new need
• Organizational direction
• Titles and names of key individuals
• Values of organization
• Special information processing circumstances
• Reasons for current system design
• Rules for processing data

7.10
11
Analyzing Procedures and Other Documents

• Four types of useful documents
• Written work procedure for an individual or a
  work group
• Describes how a job is performed
• Includes data and information used and created in
  the process of performing the job or task
• Formal systems official way a system works as
  described in the organizational documentation.
• Informal system the way a system actually works
• Business form
• Explicitly indicate what data flow in or out of a
  system and which are necessary for the system to
  work
• Report generated by current systems
• Enables the analyst to work backwards from the
  report to the data that generated it companys
  performance is past years
• Description of current information system
• If the current system is computer based

7.11
12
Modern Methods for Determining Requirements

• Joint Application Design (JAD)
• Similar to group interview as it brings together
  key users, managers and systems analysts
• Purpose collect system requirements
  simultaneously from key people
• Particular structure of roles and agenda is
  followed and analysts control the sequence of
  questions answered by users
• Conducted off-site to keep participants away from
  distractions
• may last from four hours to an entire week and
  may consist of many weeks
• Prototyping
• Repetitive process
• Rudimentary version of system is built
• Replaces or augments SDLC
• Goal to develop concrete specifications for
  ultimate system

4.12
13
Joint Application Design (JAD)

• Participants
• Session Leader organizes and runs the JAD
• Users key users of the current system
• Managers of the workgroups who use the current
  system
• Sponsor needed to cover expenses
• Systems Analysts to learn from users and
  managers
• Scribe takes notes
• IS Staff other IS staff like programmers,
  database analysts
• JAD sessions are usually held in special-purpose
  rooms where participants sit in a horse-shoe
  shaped tables.
• rooms have whiteboards, audio-visual tools
  like overhead projectors, flip charts,
  transparencies

4.13
14
Joint Application Design (JAD)

• 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

4.14
15
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
• 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

7.15