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nowtOrganisational StructureLife Cycle of MISCorperate StrategyInformation Data and KnowledgeManagement of ChangeLegal IssuesTrainingProject ManagementInformation and the Professionalnowt
endIS in organisationsDevelopment of ISLife Cycle of ISSuccess or failure of ISQuestionsend
 

MIS Life Cycle

The introduction or upgrading of an information system is likely to have far reaching consequences for an organisation. It will affect and be affected by the organisational structure. Properly implemented it may have the capability to turn a loss making organisation into profit. It is also likely to represent a tremendous cash investment by the organisation - not only for the hardware and software but also in associated costs of training and changeover.

It is not surprising therefore that formal methods of developing an information system have grown up in an attempt to avoid poor implementations that could put an organisation out of business. In particular the organisation will attempt to control the cost of the implementation and the time scale over which it is developed. Information Systems are notorious for overrunning budget and falling behind deadline.

Control is exercised by breaking system development down into stages.

Preliminary Survey An initial survey establishes whether or not a new system is needed. The survey will normally be prompted by a perception within the organisation's management that the existing system is not performing as required - staff may be unhappy or performance/productivity may by falling or it may simply be that there is a feeling within the senior management that developments in IT should allow a more effective system to be implemented. If the preliminary survey identifies a problem then the objectives of the system will be defined at this stage.
Feasibility Study The existing system is looked at briefly and various alternatives (such as replacing the existing system or upgrading it or extending it) are considered. A formal report is prepared for management identifying the solution the greatest cost benefit. Management can then decide whether or not to proceed to the next stage
System Investigation Information about the existing system is collected. Methods used to carry out the system investigation will include looking at existing system documents, questionnaires, interviews and direct observation.. This information will be used to determine the information requirements of the system during the design stage. As part of the system investigation the remaining stages will be described and a time scale determined.
Systems Analysis At this stage the information gathered during the system investigation is used to analyse the existing system, determining exactly what functions it performs and what problems need to be overcome. One outcome of this stage will be a requirements specification that details exactly what the organisation requires from the system. Methods used at this stage include data modelling - producing the data requirements in terms of entity mappings, process modelling - defining the processing requirements in terms of events and the operations that they trigger and system modelling in which the interrelationship between functional areas (e.g. orders received, order processing, goods dispatch) are defined.
System Design The system design results in a system specification document which will be agreed between the management and the design team. As the project develops the system specification document will be updated to reflect new design decisions. This stage will include the design of output, input, files and documents to be used by the system. This will involve specifying the format and content of input/output and the structure of data files.
Design will normally be structured to follow a top-down methodology. The overall problem will be broken down in to smaller and smaller sub-problems which will then be solved
System Implementation The system is produced. Program code is written so that the design specified in the design stage is turned into a real system. The system is tested, staff trained and old files converted to the new system or new files set up and the existing system is changed over to the new one. Changeover may be direct - the old system is discontinued and the new one takes over or parallel - where the new system is run alongside the existing until it is bedded in. An alternative is to run the new system as a prototype.
Review and maintenance The System delivered is measured against the system requirements documentation and its performance monitored. Inevitably some aspects of performance will be unsatisfactory and this will lead back to the first stage of the system life cycle which then repeats over again.
   

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