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Requirements

Analysis

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Identifying Requirements

Correct systems can only be built if you know exactly

System Requirements

Defines the services the system is to provide and

prescribe constraints for its operation

Functional

Requirements

Nonfunctional

Requirements

what the

user needswhat the systemmust do

Therefore most important factors in building correctsystems is to first clearly define what the system must do

System Analyst

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Identifying Requirements.System requirements can be developed

by discussing with users their requirements

building systems that satisfy these requirements

Importance of Communication

- Analyst must ensure that no ambiguities arise in discussions

between various people involved in analysis

- Different jargon use by different people may cause problems

Example: Ambiguous Requirement Statement

Identify a transportation to transfer a single

individual from home to place of work

Management

Interpretation IT Interpretation User Interpretation

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Requirements Discovery Methods

Requirements Discovery

Includes techniques to be used by systems analysts to identify

or extract system problems and solution requirements from theuser community.

System Analyst

Requirement discovery for a system

depends on the analysts ability to first

discover and then analyze problems

and opportunities that exist in the

current system

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Requirements Discovery Methods..

It is the formal process of using techniques to collect information about

systems requirements etc. It is also called Information gathering

Fact-Finding

Fact-Finding Methods

Sampling of Existing

documentsResearch

andsite visits

Observations

of the work

environment

Questionnaires

Interviews Prototyping

Joint

requirements

planning

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Requirements Discovery Methods..

First document that analyst should seek

out is the organizational chart

Be sure that they are relevant and

up-to-date

Sampling of existing Documentation

Documentation Forms Files

When you are studying an existing system, you

can get a good idea by studying existing

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Requirements Discovery Methods..Research and Site Visits

Thoroughly research the application and problem.

Good sources ofinformation

Computer trade

Journals

Intranets

Identify the material that are relevant and reliable

Reference books

Internet

World Wide Web

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Requirements Discovery Methods..

Observations of the work environment

Systems Analyst participates in or watches aperson perform activities to learn about the system

often used when validity of data collected through other

methods is in question orwhen the complexity of certain

aspects of the system prevents a clear explanation by theend users.

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Requirements Discovery Methods..

Observations of the work environment

Advantages

Data gathered by observation can be highly reliable

Relatively inexpensive

Allows system analyst to do work measurements

Etc.

Disadvantages

People usually feel uncomfortable when being watched.

Work being observed may not involve the level of difficulty or

volume normally experienced during that time

Etc.

I dont like

being watched

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Requirements Discovery Methods..

Questionnaires

Advantages :

Questionnaires are special purpose documents that allow the

analysts to collect information and opinions from a largeaudience.

Most questionnaires can be answered quickly

Relatively inexpensive way of gathering data.

Allow individuals to maintain anonymity

Responses can be tabulated and analyzed quickly etc.

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Disadvantages:

Requirements Discovery Methods..

Questionnaires

The number of respondents is often low

Mostly suited for close questions

No guarantee that an individual will answer or expand

on all the questions

Good Questionnaires are difficult to prepare

No immediate opportunity to clarify a vague or

incomplete answer to any question.

Etc.

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Types of Questionnaires

Free-format: A question is asked, and the respondent recordsthe answer in the space provided after the question.

Fixed-format: contains questions that require specific responsesfrom individuals

Requirements Discovery Methods..Questionnaires

1. multiple-choice questions

2. rating questions

3. ranking questions

-Given several answers to select one. Eg. Yes, No type

-Given a statement and asked to use supplied responses to

state an opinion.

-Given a several possible answers to be ranked in order of

preference or experience

There are 3 types of fixed-format questions

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Requirements Discovery Methods..

Most commonly used technique

in analysis

Systems analyst collects

information from

individuals face to face.

Systems Analyst must possess

good human relations skills for

dealing effectively with different

type of people

Interviews

Can be used to achieve any of the following goals:find facts, verify facts, clarify facts, generate enthusiasm,

get the end-user involved, identify requirements, and solicit

ideas and opinions.

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Requirements Discovery Methods..

Gives the analyst an opportunity to motivate the

interviewee to respond freely and openly to

questions.

Interviews

Advantages

Allow the analyst to look for morefeedback from the interviewee.

Permit the analyst to ask questions

from each individual etc.

New ideas may arise

Motivation

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Requirements Discovery Methods..

Interviews

Disadvantages

Very time consuming. Therefore costly approach

Success of interviews is highly dependent on thesystems analysts human relations skill.

Interviews may be impractical due to the location of interviewees

etc.

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Requirements Discovery Methods..

Interviews

Types of Interviews

Unstructured interviews..

Types of Interview Questions

Open-ended questions

Closed-ended questions

Structured interviews..

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Requirements Discovery Methods..

Interviews

How to conduct an Interview?

Select Interviewees

Interview the end users of the information system you are studying.

A formal organizational chart will help you identify these

individuals and their responsibilities.

Always make an appointment with the interviewee.

Higher the management level of the interviewees,

less time should be spent.

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Requirements Discovery Methods..

Interviews

How to conduct an Interview?...

Prepare for the Interview

Prepare an interview guide - checklist of specific questions

interviewer will ask the interviewee

Avoid the type of questions such as:

Loadedquestions (Do you need to include both of these columnsfor this report?)

Leadingquestions (You are not going to use this operator code, areyou?)

Biasedquestions (How many codes do we need for foodclassification in the inventory file? I think 20

should cover it ?)

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Requirements Discovery Methods..

Interviews

How to conduct an Interview?...

Prepare for the Interview

Interview question guidelines :

Use clear and concise languageDont include your opinion as part of a

question

Avoid long or complex questions

Avoid threatening questionsverify before you leave

The purpose of the interview is to investigate,

not to evaluate or criticize

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Requirements Discovery Methods..

Interviews

How to conduct an Interview?...

Conduct the Interview

Interview Opening : Intended to influence or motivate theinterviewee to participate

Interview body : Obtain interviewees response to your list ofquestions

Interview conclusion : Express your appreciation. Importantfor maintaining good relationship and trust.

The actual interview

consist of threephases:

Conclusion

Body

Opening

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Requirements Discovery Methods..

Prototyping

A method used to test or illustrate an idea and build a system in an

explorative way. Used to discover user requirements

Allows analyst to quickly create mock forms and tables to simulate

the implemented system.

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Requirements Discovery Methods..Prototyping

Advantages

Allow users and developers to experiment with the software anddevelop with an understanding

Helps to determine feasibility and usefulness of the system

Minimize the time spent for fact-finding and help define morestable requirements. Etc.

DisadvantagesDeveloper may need to be trained in the prototyping

approach

Prototype can only simulate system functionality and are

incomplete in nature. Etc.

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Requirement Discovery Methods

Highly structured group meeting are conducted to analyze problems

and define requirements. JRP is a subset of a more comprehensivejoint application development or JAD technique

JRP Participants

SponsorServe as JRP champion. Single person who is in top management.FacilitatorSingle individual who plays the role of the leader or facilitator.

Joint Requirement Planning (JRP)

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Requirement Discovery Methods

JRP Participants

User and Manger

Number of participants from the user and management.

ScribesThose who are keeping responsible for keeping records pertaining to

everything discussed in the meeting.

IT StaffIT personal who primarily listen and take notes regarding issues and

requirements.

Joint Requirement Planning (JRP)

For more details refer - Ref_1: page 213-239

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Document Analysis

Documents of a SystemDocumentation is both a communication tool and a management

tool.

It is a communication tool : because it contains a repository of all work done to date and

makes it available to all persons working on related parts of alarge project.

Such a repository can prevent unnecessary repetitions whensomeone leaves the project team.

Proper documentation ensures that all the informationdeveloped about the system is always available to new

people joining the project.

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Document Analysis

Documents of a System

Documentation is also a management tool.

It supports management in two ways: gives access to the latest work to all project personnel and

thus reduces the chance of work having to be repeated.

is the only project deliverable, specially in the early project

phases, and thus serves to determine project status and

progress.

Is also a part of the phase output.

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Document Analysis

Document Flow Diagrams

Used to examine the flow of documents within the existing system.

Example: Order

Invoice

Delive

rynotes

Supplier

Purchasing

Dept

Stores

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Document Analysis

Advantages / Usefulness

Used to identify the documentsin the system

Identify the flow of document

To understand the workflow of

the existing system

Used to define the system

boundary

Used to draw Data FlowDiagrams by further analyzing

Etc..

For more details refer - Ref_4: pages 29-34

Document Flow Diagrams