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CB 101
Concept of ANALYSIS AND DESIGN

Requirements Analysis

Week 2

Learning Objective
To list the requirement before implementing the new system ? To differentiate the types of requirements ? To elaborate requirements-gathering techniques in the requirement analysis process ? To document the requirements in List of Requirements
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What is a requirement?
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A requirement is a statement of what the system must do or what characteristic it must have. Requirements in analysis part are written from business person perspective (business requirements/ user requirements) and focus on what of the system. Requirements in design part are written from developer’s perspective (system requirements) and describe how the system will be implemented.

Why User Requirements?
Need to understand how the organization operates at present ? Define the problems with the current system ? Define the requirements users have of a new system that are not in the current system
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Current System VS New System
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Sections of the current system no longer meet the needs of the organization. Some aspects of the organization’s work are not covered by the current system. The system can no longer evolve but needs to be replaced. It is important to understand current system to carry functionality forward into new system. It is also important to understand it so that shortcomings and defects can be corrected in the new system.

Reasons for Investigating the Current System
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Functionality is required in new system Data must be migrated into new system Technical documentation provides details of processing algorithms Defects of existing system must be avoided Parts of existing system may have to be kept We need to understand the work of the users Baseline information about the existing system helps set targets for the new one

Reasons For Finding New Requirements
Organizations operate in a rapidly changing business environment ? Organizations operate in a changing technical environment ? Organizations merge, unmerge, take over and get taken over ? All this drives the need to replace systems and build new ones
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Types of Requirements
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Functional ( System services )
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scope of the system necessary business functions

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Non-functional ( System constraints )
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regarding ‘look and feel’, performance, security, etc. also known as supplementary requirements

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Functional Requirements
A process the system has to perform and describe what the system must do. ? Include:
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processes ? interfaces with users and other systems ? Data or information
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Example:
The student registration system must have ability to search selected student based on Student ID number. ? To report actual and budgeted expenses.
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Non-functional Requirements
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Refer to behavioral properties that the system must have. Concerned with how well the system performs such as usability and performance. Include: ? Operational – the physical and technical environment in which the system will operate. ? Performance - response times, capacity (volumes of data) and reliability of the system ? Security considerations ? Cultural and political – cultural, political factors and legal requirements that affect the system Example: ? Be accessible to Web user ? Any interaction between the user and the system should not exceed 2 seconds. ? Only direct manager can see personnel records of staff. ? The system shall comply with insurance industry standards

Requirements-gathering Techniques

Traditional Methods
Background Reading ? Interviewing ? Observation ? Document Analysis ? Questionnaires
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Modern Methods
Joint Application Design (JAD) ? Prototyping
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Background Reading
To understand the organization and its business objectives ? Includes:
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reports ? organization charts ? policy manuals ? job descriptions ? documentation of existing systems
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Background Reading….
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Advantages:
helps to understand the organization before meeting the people who work there ? helps to prepare for other types of fact finding ? documentation of existing system may help to identify requirements for functionality of new system
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Background Reading….
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Disadvantages:
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written documents may be out of date or not match the way the organization really operates

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Appropriate situations:
analyst is not familiar with organization ? initial stages of fact finding (Eg: objectives of organization)
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Interviewing
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Most widely use. To get an in-depth understanding of the organization’s objectives, users’ requirements and people’s roles Requires most skill and sensitivity. Includes:
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managers to understand objectives staff to understand roles and information needs customers and the public as potential users domain experts

Interviewing…
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Structured (formal) interview
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Open-ended questions (unanticipated responses)
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conversational, questions with no specific answers in mind. - E.g.: What do you think about the current

system?
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Closed-ended questions (a list of possible responses

known)
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structured, questions with limited range of possible answers - E.g.: What information is missing from the monthly sales report?

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Unstructured (informal) interview

Interviewing…
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Advantages:
personal contact allows the interviewer to respond adaptively to what is said ? it is possible to probe in greater depth ? if the interviewee has little or nothing to say, the interview can be terminated
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Interviewing…
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Disadvantages:
can be time-consuming and costly ? notes must be written up or tapes transcribed after the interview ? can be subject to bias if the interviewer has a closed mind about the problem ? if interviewees provide conflicting information (different interviewees) this can be difficult to resolve later
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How to Conduct Interviews

Interview Guide is a document for developing, planning, and conducting an interview.

Each question in an interview guide can include both verbal and non-verbal information.

Interviewing…
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Appropriate situations:
most projects ? Provide information in depth about the existing system and about people’s requirements from a new system
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Document Analysis
Review of existing business document (to understand current system) ? Can give a historical and formal view of system requirements. ? Includes:
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Paper reports Memos Policy manuals Use training manuals Form Screen shots of existing computer system

Document Analysis…
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Advantages: ? for gathering quantitative data ? for finding out about error rates Disadvantages: ? not helpful if the system is going to change dramatically ? probing is possible only if original author is available Appropriate situations: ? always used to understand information needs ? where large volumes of data are processed ? where error rates are high ? where provide statistical data about volumes of transaction and pattern of activity.

Business form is a document that contains useful information regarding data organizations and possible screen layouts.

Questionnaires
A set of written questions obtaining the views of a large number of people in a way that can be analysed statistically ? Includes:
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web-based and e-mail questionnaires ? open-ended and closed questions ? gathering opinion as well as facts
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Questionnaires…
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Advantages:
economical way of gathering information from a large number of people ? effective way of gathering information from people who are geographically dispersed ? a well designed questionnaire can be analysed easily ? Short time ? Less bias in interpreting the results.
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Questionnaires…
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Disadvantages:
good questionnaires are difficult to design ? no automatic way of following up or probing more deeply
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Questionnaires…
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Appropriate situations:
when views of large numbers of people need to be obtained ? when staff of organization are geographically dispersed ? for systems that will be used by the general public and a profile of the users is required
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Observation
The act of watching processes being performed. ? It enables the analyst to see the reality of a situation, rather than listening to others describe it in interviews or JAD sessions. ? To check the validity of information gathered from indirect sources such as interviews and questionnaires.
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Observation….
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Includes:
seeing how people carry out processes ? seeing what happens to documents ? obtaining quantitative data as baseline for improvements provided by new system
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Can be open-ended (get out to observe what happen and note it down) or closeended (draws up an observation schedule/form to record data)

Observation….
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Advantages:
first-hand experience of how the system operates ? high level of validity of the data can be achieved ? verifies information from other sources ? allows the collection of baseline data (data about performance of the existing system and users)
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Observation….
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Disadvantages:
people don’t like being observed and may behave differently, distorting the findings ? requires training and skill ? logistical problems for the analyst with staff who work shifts or travel long distances ? ethical problems with personal/private/sensitive data (bank or governmental data)
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Observation….
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Appropriate situations:
when quantitative data is required ? to verify information from other sources ? when conflicting information from other sources needs to be resolved ? when a process needs to be understood from start to finish
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Joint Application Design (JAD)
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JAD is a technique for gathering business software requirements. The purpose is to bring together the technical/creative team and the business community in a structured workshop setting to extract consensus based software requirements. The client involves throughout the development process in order to get the requirement satisfaction. Team members meet in isolation for an extended period of time Highly focused

JAD Team Members
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Session leader Users Managers Sponsor Systems analysts Scribe IS staff (programmer, DB analyst, center personal)

coordinator information source information source champion listeners recorder listeners IS planner, data

JAD session held in special-purpose room where participant sit around horseshoe-shape table

Prototyping
A repetitive process in which analysts and users build a rudimentary version of an information system based on user feedback ? Still have to interview user and collect documentation. ? Repeated cycle: build, use, evaluate
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Prototyping…
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Prototyping is good when: ? Users are unclear about their requirements (especially for new system or system that support decision making). ? The system affects a relatively small number of users. ? Designs are complex. ? Communication between users and analysts needs to be strengthened. ? Rapid application development tools (form/report generator) are available to build system rapidly.

User Involvement
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A variety of stakeholders (all people who stand to gain from implementation of the new system):
senior management—with overall responsibility for the organization ? financial managers—who control budgets ? managers of user departments ? representatives of users of the system
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User Involvement…
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Different roles of users:
evaluators of prototypes ? testers ? as trainees on courses ? end-users of new system
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Documenting Requirements
Documentation should follow organizational standards ? CASE tools that produce UML models maintain associated data in a repository ? Some documents will need separate storage in a filing system:
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interview notes copies of existing documents minutes of meetings details of requirements

Documenting Requirements…
Documents should be kept in a document management system with version control ? Use use cases to document functional requirements ? Maintain a separate requirements list for non-functional requirements ? Review requirements to exclude those that are not part of the current project
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Documenting Requirements…
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How to document the requirements?
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The requirements must be documented in List of Requirements

Activities Involved In Capturing Requirements
Requirements Analyst Project Initiation Document Elicit requirements Glossary Candidate Requirements Select requirements

Requirements List

Develop use cases

Use Case Model


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