analysis phase purpose of information systems in organisations information systems exist in...

ANALYSIS PHASE

Purpose of information systems in organisations

• Information systems exist in organisations to serve organisations.

• Therefore the aims and objectives of an information system are directly related to the aims and objectives of that organisation.

• In the process of Information Systems Analysis, organisational aims and objectives are described with increasing detail in the sequence,

• a mission statement, organisational goals and operational goals.

Organisational Goals

• Business are organisations that generally have profit as a goal.

• Some common goals of both commercial and non-profit organisations are – providing a high standard of customer service, producing

excellent quality goods, etc. • A main reason why individuals and organisations

create information systems id directly related to the achievement of their primary goals.

Examples of goals

• Increase market share• Improve service• Achieve efficient work practices• Increases profits• Reduce wastage of resources• Provide most extensive range of profits within the

industry.

• The goals of an individual or an organisation are clearly the reason behind the purchase of an information system, however the operational objectives usually determine the size and types of the information used.

• Operational Goals are likely to be concerned with the efficiency and effectiveness of the operations of the organisation, or the work of the individual employees.

Problems in Organisations

• Problems arise within organisations that cause the organisation’s aims and objectives not to be achieved.

• There are 2 types of problems.• There’s an immediate problem that prevents a

product or service being provided adequately.• A person may have an idea that may enable the

aims and objectives of the organisation to be better achieved.

• If the source of these problems lies with the information system of the organisation, the information system probably needs changing or replacing.

• An information System Investigation needs to be undertaken if the above is the case, because it can be quite expensive to change or replace an information system and its not always clear which part of the information system needs to be changed or replaced.

• The information systems investigation process moves through a number of stages.• A board investigation of the problem

and its possible solutions (Preliminary Investigation) is undertaken.• A detailed analysis of the system, it s

problems and possible solutions is undertaken.

Preliminary investigation

• In the Preliminary Investigation process, possible consequences or opportunities are pinpointed in relation to new or enhanced system. Questions asked as this stage may include:

– What problems might be solved?– What possible costs are associated with this

change?– What new opportunities may arise from the

introduction of this change?– What risks are there?– What additional hardware is needed to

enhance or replace the information system?

Defining The Problem

• Purpose of the Preliminary Investigation is to determine the scope (size or extent) of the problem, so a decision can be made about its solution. The original problems are often put in a negative form.

• The positive information problem statement contains or implies the goal or goals to be achieve I.e., what needs to be done to solve the problem.

• eg “The sales department need a computer based system to collect and process the sales for the last month at the most 3 days after the end of month.

Feasibility Study/Analysis

• Once the problem identification process has been completed, an idea for a solution/s has been established. Before any large project is approved a thorough investigation of the implications, costs and benefits of the system should be undertaken. This investigation is know as a Feasibility Study.

• There are 3 aspects to a feasibility study, all of which are equally important.

1.Operational Feasibility

• Questions to consider when performing the Operational Feasibility study:

• How will it perform? What will be the computer response time?• Is the information produced relevant, timely,

accurate, concise and complete?• Does it provide sufficient avenue to reduce costs?

• Does it provide adequate control and data security?• Does it make efficient use of resources such

as: hardware, software and personal?• Does it provide a valuable service to those

that require the data/information?• Does management support the system?

• How do end users feels about the change?• Is there any resistance to change?• How will the working environment change?• Are the project deadlines reasonable?• Are the deadlines mandatory or desirable?

2. Technical Feasibility

Three main issues are addressed in Technical Feasibility :

• Is solution practical ?• Do we currently process the technology to

meet these needs ?• Do we have the necessary technical

expertise ?

3. Economic Feasibility

• Economic Feasibility establishes whether the system is a good investment for the organisation.

• A system is deemed to be economically feasible if the expected benefits (both financial and non-financial) are more important than the estimated costs of installing, planning, purchasing and building it.

Some of cost elements evaluated in the economic feasibility study includes:–personnel costs– software licensing– training and development of software

that is not off-the-shelf– the cost of hardware

After the preliminary investigation and feasibility studies are completed a detailed investigation is then undertaken. This is done by a series of data collection techniques.

• Interviews• Direct Observation• Questionnaires• Collecting actual examples of documents• Research

Tools for analysing information systems data

• Two types of data are collected from an information system.

• Background data – data collected about the processes in the system• Application data – information that is

processed in the system

• The background and application data is analysed.using a number of tools that focus on two aspects of the system:

• The data/information & movement of data / information• Processing of data into information.

Data & Data Flow Analysis

• Context and Data Flow Diagrams (DFD) are the main tools used to pictorially represent how application data and information flow through the system.

Process analysis• One of the purposes of data flow diagrams is to

‘discover’ the processes that occur in an information system. The next step in analysing and Information System is to analyse each process in a DFD. There are a number of techniques used to this. They are:

a) IPO Diagrams• An Input Processing Output diagram describes the

sequence of inputting data, processing it and output information in more detail.

b) Grid Charts• Grid Charts is a table that shows relationships b/w

different parts of the system. E.g. a grid chart can be used to show all the databases used by different applications

c) Decision TreesA decision tree is a diagrammatic technique used to

describe processing. It’s a useful way of describing a number of decisions at various stages and actions that result form the decisions made.

d) Decision tablese) Flow chartsf) Structured English (pseudocode)

Other factors to consider when analysing a system

• Robustness and useability• Efficiency and effectiveness• Speed of processing data• Initial and ongoing costs• Compatibility of system components

• Personnel factors• Organisational requirements• Data protection and integrity• Health and safety issues• Legal issues

Logical Design Of A New/Modified System

• All data gathered forms the basis of the LOGICAL DESIGN for the new system– a description of what needs to be achieved.

• The LOGICAL DESIGN specifies a list of key criteria (targets) that the new system must achieve for the problem to be solved. .

• The criteria are:– the performance aims and objectives of the

new system and – the other factors, operational, technical and

economic, which need to be considered as well.

• These criteria are used to assess the various potential approaches to solving the problem, and later, to evaluate the new system when it is completed.

Alternative System Design Approaches (Logical design)The development team needs to consider what

approach needs to be taken to solve the problems.

• There are two main approaches to the further development of the new system:

(1) Top-Down(2) Bottom - up

• The choice between these 2 approaches is fundamental to the design and development of the whole project.

Top-Down And Bottom-Up Design

• Top-Down – beginning from scratch, and designing and building a completely new system by starting with the main aims of the system and then breaking them down into smaller sub-systems, sub – sub – systems.

• Bottom up – patching up an old system or using parts of an old system to determine much of the structure of the new system.

• Generally, bottom – up approaches are used more often as it is easier to use parts of an existing system rather than starting from scratch.

Rapid Application Development (RAD)

• RAD provides a number of tools to help quickly develop applications, especially GUI’s and Multimedia and database applications that would normally take a long time to develop. Two popular RAD systems for Windows are Visual Basic and DELPHI.

Prototyping

• A prototype is an early, but smaller working and/or partially complete ‘no frills’ version of the information system.

• With this approach the designer can demonstrate various alternative features to the users. If the user feedback indicates that there are any problems with the prototype system it can be modified and then re-assessed again.

• The actual prototype can be a program developed using a RAD tool, or simulation of processing using a spreadsheet, or input and output screens and reports using a word processor.

Assessment of alternative approaches

• Often the analysis can lead to the identification of a number of optional solution approaches. Also within the same approach that has been selected there are usually different technical alternatives.

• Eg replacing part or the whole of the system, different types of networks, different types of computers, mainframe versus server networks and down to different types of printers might need to be considered.

• Software alternatives can include those of custom-made versus off-the-shelf software.

• The various alternatives or options need to be listed and their strengths and weaknesses evaluated against the proposed aims and objectives of the new system, and other factors that need to be taken into consideration.

• Assessments of alternative design/development approaches are usually carried out by using a Feasibility Analysis Matrix, which incorporates the areas of operational, technical and economic feasibility as well as the objectives of the new system.

The Next Step

• Once a decision has been made the next step is to pass the logical design to the design team that will produce a physical design for the new or modified system that will again be assessed against the key criteria.