Systems Analysis and Design Part 1 Analysis Stage - SEE-ICT
Transcription
Systems Analysis and Design Part 1 Analysis Stage - SEE-ICT
Systems Analysis and Design Part 1 Analysis Stage Systems Analysis and Design As businesses grow, they will need to look at how they process their data. Developing new systems is very expensive in time, people, and money. The way a company approaches this task is vital to its success as a business. The systems life cycle Systems of any kind have a life cycle. Systems are created, they develop, they mature, they eventually lose their efficiency, then they are replaced. The systems analyst will follow this life cycle to complete the stages that take place when a system is being designed and developed. Collecting data for analysing the current system There are four main ways to collect information about the current system, as it is being used at the moment, each having advantages and disadvantages. The systems analyst must decide depending on the current situation what methods he will use to collect information from the people who work on the system first-hand. Collecting data for analysing the current system The systems analyst will use the following four ways to collect system information he requires from the current system users. • Interviews • Observation • Questionnaires • Using existing documentation In pairs, takes 10 minutes to use the internet to search for information, and write notes about data collection methods Interviews Description Advantage Disadvantage Observation Description Advantage Disadvantage Questionnaires Description Advantage Disadvantage Using existing documentation Description Advantage Disadvantage Based on your findings, decide which would be the best way to collect information in the following situations Situation A small group of people have detailed knowledge of the current system Only a few people have limited knowledge of how the present database is constructed You need to understand how information and documents move around the organisation Many people have views about how effective the current system is and who can provide answers to a number of specific questions Method Method Observation Description Involves watching personnel using the existing system to find out exactly how it works. Advantages The analyst obtains reliable data. It is possible to see exactly what is being done. It is a relatively inexpensive method. Questionnaire Involves sending out The questions can be s questionnaires to answered quite quickly. the work force and/or to customers to find out their views of the existing system and find out how some of the key tasks are carried out. It is a relatively inexpensive method. Individuals can remain anonymous if they want. It allows quick analysis of the data. Disadvantages People are generally uncomfortable being watched and may work in a different way. If workers perform tasks that violate standard procedures, they may not do this while being watched! Often the number of returned questionnaires is low. The questions are rather inflexible since they have to be generic. There is no immediate way to clarify a vague or incomplete answer to a question. Method Interviewing Looking at existing paperwork Description Involves a one-toone question-andanswer session between the analyst and the employee/customer. Advantages It gives the opportunity to motivate the interviewee into giving open and honest answers to the analyst's questions. It allows the analyst to probe for more feedback from the interviewee, as it is easier to extend a question. It is possible to modify questions as the interview proceeds and ask questions specific to the interviewee. It is a good method if the analyst wants to probe deeply into one specific aspect of the existing system. Allows the analyst It allows information to be to see how the obtained which was not possible paper files are kept, by any of the other methods. look at operating The analyst can see for instructions and themselves how the paper training manuals, system operates. It allows the check the accounts, analyst to get some idea of the etc. scale of the problem, memory size requirements, type of input/output devices needed, etc. Disadvantages It can be rather time consuming. It is relatively expensive, due to the use of the analyst's time. The interviewee cannot remain anonymous. It can be very time consuming. Because of the analyst's time, it is a relatively expensive method. Information collection Once the systems analyst has collected as much information as he can, he will bring it together in a way so that the current system can be described fully. He will create flowcharts to show the flow of information, where it is stored, how it is accessed and by whom. This will make it possible for the system analyst to determine the strengths and weaknesses of the current system. Outcomes of Analysis Stage The outcome will be a report to management outlining the requirements that any new system should fulfil. people call it the “terms of reference” as it can be used as a reference, in order to ensure that any design proposal does in fact meet the set of requirements. Some