Systems Analysis

Systems Analysis

Lecture 5

Requirements Investigation and Analysis

1BTEC HNC Systems Support Castle College 2007/8

Lecture Objectives

• Systems analysis phase activities

• The need for user involvement in requirements modeling

• Explore the initial fact finding stage and the steps involved




RequirementsModelingModeling

Data and Process

Development Strategies

Systems Analysis PhaseMajor

Activities

Requirements Modeling

• Required inputs/required outputs• Processes• Performance• Security


To describe and identify the requirements of a new system we need to first gather the facts:

Definitions

• Outputs refer to electronic or printed information produced by the system

• Inputs refers to the necessary data that enters the system – either manually or in an automated manner

• Processes refer to the logical rules that are applied to transform the data


Definitions (cont.)

• Performance refers to system characteristics such as speed, volume, capacity, availability and reliability

• Security refers to hardware, software and procedural controls that safeguard and protect a system and its data from both internal and external threats


Other areas to consider

• Batch v Real Time• Basic Architecture• Backup and Recovery• User Support


Perform Fact finding

Fact finding involves various techniques and may consume several hours, days or weeks Fact finding involves the following: • examining organisational charts, • conducting interviews, • reviewing documentation, • observing operations, and • conduct a user survey.


SQIRO

One way to remember fact finding methods is the pneumonic ‘SQIRO’

• Sampling – (examination of results)• Questionnaires (conduct a survey)• Interviews (with key personnel)• Research (Reading)• Observation –(of operations performed)


Info gathering model building

Understand new system’s:


QuestionnairesQuestionnaires

InterviewsInterviews

SamplingSampling

ObservationObservation

ResearchResearch

Develop requirements

and models

Develop requirements

and models

ProceduresProcedures

ConstraintsConstraints

FunctionsFunctions

Organisational Charts

• An analyst will study an organisational chart in order to understand how the department(s) function

• This means that you can identify those people you wish to interview

• Organisational charts show formal reporting relationships between staff members


Conduct Interviews

The interview process involves the following steps:• Determine the people to interview• Establish objectives for the Interview• Develop interview questions• Prepare for the interview• Conduct and then document the interview• Evaluate the interview


An interview is the primary method of obtaining information (Shelley et al p69)


Review Documentation

• The analyst will also want to revue the current documentation

• The documentation describes the processes and situation with/of the present system


Observe Operation

Another fact finding method is to observe the current system in operation


• This will show how workers carry out a particular task

• It could include Sampling the inputs or outputs of the system

Conduct a user survey

• Less time consuming than interviews

• Information can be obtained from a larger group of users

• Surveys involve a questionnaire (form that users complete)

• Less expensive and can include a cross section of people


Evaluate Feasibility

• Economic Feasibilities

(Cost/benefit analysis; current cash flow)

• Technical Feasibilities

(Risk – new technology; lack of expertise)

• Operational Feasibilities (Cultural)

(Longstanding work procedures; Shift in power; Fear – change, technology, loss of employment, loss of control)


Evaluate Feasibility (cont.)

• Schedule Feasibilities

(Develop schedule; high risk – assumptions and estimates, end date)

• Resource Feasibilities

(Skilled team members at right time, computer resources, physical facilities, support staff)


2 – Data Process Modeling• Data and process modeling

continues the modeling process by representing graphically (or conceptually) data and processes

• There are various methods for doing this, which we will learn about in later lectures and through practical case studies, e.g. Use case models, data flow diagrams, etc


3 – Development Strategies

This phase is concerned with software trends, acquisition and development alternatives for the new system

“The development strategies phase, considers various development options and prepares for the transition to the Systems Design Phase of the SDLC” (paraphrased from Shelley et al p92)


Methodologies and Options

• Also called Development strategies

• During project planning, it is necessary to choose from a range of methods

• Each methodology (development strategy) uses different techniques to achieve the objectives of the new system requirements


Methodology 1 – Structured Analysis

• Often called the ‘Traditional method’ and used extensively in the early days of IT development

• Structured Systems Analysis and Design Methodology (SSADM)

• This methodology treats processes and data as separate entities

• Techniques used include Data flow diagrams


Alternatives to ‘Traditional’

• IT professionals now recognise that successful systems must be USER ORIENTED

• Users need to be involved formally or informally at every stage of the system development


Result: Team orientated methods and techniques

“Top managers expect the IT Department to deliver the best possible information system at the lowest possible cost in the shortest possible time” (p93 Shelley et al)

To fulfill these expectations many IT managers have tried to increase user participation


Activity

Consider the 3 stages we have just examined:

Write one or two sentences to explain what your stage is and what the analyst needs to do at that stage


1. Requirements modeling – A students

2. Data and Process modeling – B students

3. Development strategies – C students

Defining the ‘Deliverable’

• System Requirements Document– This is an overall requirements

definition for the new system

• Project management – Is now needed to co-ordinate

people, tasks, timetables and budgets


Requirements Specification(s)

• Clear, professional, thorough

• Easy to understand and follow

• Use diagrams / charts where possible

• From highest level, drill down to more detail

• Within Project Vision

• Include Recommendations28BTEC HNC Systems Support Castle College 2007/8

Project Management

• The system requirements document provides the ‘blueprint’ of what is needed for the new system

• The Project management team then decide upon the best methods to achieve these requirements

• There are a number of Methodologies from which to choose


Present results and recommendations• The final task in the Preliminary

investigation is to prepare a report for management and possibly deliver a presentation

• This feedback includes an estimate of the costs and benefits of the proposals and recommendations

• Good oral and written communications are essential at this stage…


Oral presentations are often required allowing for questions and answers


In Conclusion

• Systems analysis phase activities

• User involvement

• Requirements modeling

• Examined the steps in initial fact finding


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