ICT WJEC A2 - TOPIC 9: SYSTEM DEVELOPMENT LIFE CYCLES

• INTERVIEWS:- conducted with different levels of the organisation

advantages: can gather large amounts of information/ make judgements on how valid an answer is based on body language/ can ask follow-up questions

disadvantages: time consuming and expensive/ the interviewer needs to be trained/ difficult to analyse a large amount of information (detailed)

• QUESTIONNAIRES:- send out and then stategically analyse responses [suitable when staff are spread over a wide geographical area]

advantages:relatively cheap to produce for a large amount of people/ can be distributed worldwide/ could be completed online (meaning the results would be recieved faster)

disadvantages: designed by experts (cost)/ people are too busy s othey cannot always find time to complete a questionnaire/ the answers arent always truthful

• OBSERVATION OF CURRENT PROCEDURES:- "time and motion" study to see where procedures could be done more efficiently (collecting the information first hand)

advantages: can actually see what is happening (do not have to rely on what other people tell you regarding it)

disadvantages: very time consuming and expensive/ staff might feel as though they are being watched, and then start acting differently (... not giving a true representation)/ cost of sending analysts around the country

• DOCUMENTATION INSPECTION:- examine current business and systems documents and outputs (eg. invoices)

advantages: can see how the current system should be operating/ inexpensive method of gathering lots of information quickly

disadvantages: documents may not be up-to-date, so they dont reflect the system changes

FEASIBILITY REPORT: the summary of an initial investigation to look at the likelihood of being able to create a new system with stated aims and objectives at reasonable cost- the document is used by senior managers to assess whether it is worth continuing with the project.

should include:

• user requirements (aims and objectives)
• definition of the scope of the present system (outline the current system)- organisational chart, define sources of data, methods of data capture
• major data processing functions (data flow)
• identifying problems with the current system
• cost benefit analysis
• potential improvements (benefits of the new system)
• conclusions.. is it worth proceeding?

• design of hardware
• design of software- specification
• design of data and file structures that will allow a useable system to be built- includes the design of tables etc. for a relational database
• design of input methods - include the design of forms (data capture/ on-screen...) used to input the data
• design of processes- queries/ macros/ calculations
• design of output- reports/ specialist documents (eg. invoices, payslips...)
• design of information systems will allow users to extract information for decision making
• design of networks and transmissions eg. topology, type of cable...

• PARALLEL CHANGEOVER:- old ICT system runs alongside the new ICT system for a period of time until the staff are happy it is working properly.

advantages: minimise the risk of in introducing a new ICT system/ can compare the results and make sure that it is working properly

disadvantages: lots of unnecessary work (as work has to be done twice for a period of time)- this is expensive and takes time/ adds to the amount of planning needed for implementation

• DIRECT CHANGEOVER:- [if the old and new systems are incompatible] stop using the old system one day and start using the new one the next day.

advantages: requires fewer resources provided nothing goes wrong

disadvantages: if the system fails then can be disasterous for the business/ cutting edge (hardware/ software)

• PHASED CONVERSION:- a module at a time can be converted to the new system in phases until the whole system is transferred.

advantages: IT staff can deal with problems caused by one module before moving onto the next

disadvantages: only suitable for systems consisting of seperate modules

• PILOT CONVERSION:- ideal for large organisations that have lots of locations or branches where the new system can be used by one branch and then transferred to the other branches overtime.

advantages: implementation is on a much smaller manageable scale

disadvantages: takes longer to implement the system to all branches

• CORRECTIVE: bugs in the software which were not discovered during the testing may need correcting.

eg. a piece of software may crash when using it with another piece if software/ problems with reports not being printed out properly

• PERFECTIVE:improving the performance of the software.

eg. developing on-line tutorials and more help screens to help new staff learn the software/ improving the layout of the interface due to feedback that the interface is difficult to use (confusing)

• ADAPTIVE: software may need to be changed due to the changing needs of the business/ organisation

eg. a new virus/ threat means that the software will need to be adapted to protect against this/ the organisation expands so the software needs to be altered so it is able to cope with an increased number of users

CRITERIA FOR EVALUATING A SYSTEM:

• how closely does the system match the user requirements
• how easily can the system be used
• how satisfies are the users with the informaton provided by the system
• how well has the system been tested
• how reliable is the system
• how well does the system ensure security of data and programs

TOOLS FOR GATHERING INFORMATION:

• quantitative test: giving a score out of eg.5
• error logging interviews: all logs to help desk are logged
• questionnaires: users are more likely to be honest if they can remain anonymous

POST IMPLEMENTATION COSTS and METHODS TO AVOID THEM

• to avoid additional training- ensure the initial training is good enough and done to high standard
• to avoid having to make modifications-  ensure that the user requirements are fully identified at the start of the process
• to avoid having a help desk/ additional support- correct training should be given
• to avoid adding additional hardware- ensure there is plenty of additional capacity initially
• to avoid having to correct bugs- ensure that the testing process is effective and comprehensive