Welcome to the topic of System Analysis.  By the end of this topic, we hope you understand the meaning of System Analysis and the reason for carrying out this out!

  1. What is the purpose of System Analysis and Design?
    • System Analysis is the process of looking at an existing system and then designing a new system that an carry out the same task better.  For example, Payroll System.
  2. What is the System Analysis Part?
    • This is the existing system getting looked at and suggested ideas implemented.  Existing systems that need to be improved are usually:
      • Paper based system with no use of computers at all.
      • Computer based system that is no longer good enough to handle the task.
  3. What is the Design part?
    • It contains detailed plans for the proposed new system.  They help to minimize faults and errors.  These plans are like blueprints for the system.
  4. What are the stages of System Analysis?
    • There are seven stages:
      • Research:  To study the existing system.
      • Analysis:  Look at the existing system and find improvements.
      • Design:  Plan the proposed new system.
      • Testing:  Create the new system and test it.
      • Documentation:  Create the user guide for everyday users and those who will develop it further.
      • Implementation:  Place the new system into the Company.
      • Evaluation:  Decide how well the new system is working.
  5. What is Research stage?
    • In Research stage, information is collected about the present system.
  6. Explain Analysis stage.
    • Analysis is where the current situation is looked at in detail in order to figure out what changes need to be made to make the new system better than the old one.
    • Analysis stage involves the following:-
      • Collecting data about the current system.
      • Find out problems with the current system.
      • Identify inputs, processing and outputs of the current system.
      • Identify the requirements  of the new system.
      • Producing a cost benefit analysis.
  7. What are the methods of analysis?
    • There are four methods of analysis which are used to obtain the information:
      • Questionaire:
        • Prepared questions are given to the users of the system.
        • Questionnaires usually focus on simple questions and are completed by ticking or circling options or shading boxes.  The questionnaire will contain questions that are designed to extract useful information about the current system.
          • E.g.  Is this current system easy to use ?  (YES/NO)
        • Advantages
          • Questions can be answered quickly.
          • Answers are more honest as the questions can be answered anonymously.
          • Answers to the questionnaire can be analysed automatically using any OMR.
        • Disadvantages
          • People often do not complete or return the questionnaire.
          • Unclear questions cannot be explained as people are left to answer the questions alone.
          • You may get incorrect data if people may have misunderstood the questions.
          • It is hard to ask very technical or specific questions.
      • Interview:
        • Interviews take place time to time and usually involve more detailed questions than questionnaires.  The interviewer talks to people at various levels of business (Managers, Directors, employees, etc).  Different questions might be asked to different employees, for example, a Manager or Director might be asked questions focused on the exact requirement of a new system.  An employee might be asked how they use the current system or what are the problems of the current system.
        • Advantages
          • In an interview, questions can be explained if they are misunderstood.
          • More complex questions can be asked which will give more detailed findings.
          • Questions can be changed to suit who is being interviewed.
        • Disadvantages
          • Interviews take far longer time to complete than questionnaires.
          • Expensive to carry out.
          • As the person to be interviewed needs to be away from their work, so its expensive.
          • Answers may not be honest as the person being interviewed cannot remain anonymous.
      • Observation
        • This is where a System Analyst sits and watches somebody using the current system.  By observing, the Analyst can make notes about different facts.  E.g., What are the input proceses or outputs?  Are there any errors with the current system?
        • Advantages
          • Analyst can see exactly what the current system does well and not so well.
          • Not expensive to carry out as the employee is not taken away from their work.
        • Disadvantages
          • Person being watched may feel uncomfortable and work in a different way to usual.
      • Looking at the system’s document:
        • This involves looking at paper work for the current system.  The paper work will contain information needed to implement the new system.
        • Paper work can include list of stock items, employee’s pay scale, etc.  It also contains technical documentation.
        • Advantages
          • Could save time as there may be copies of previous analysis.
          • Can see existing inputs, processing and outputs.
          • Allows the Analyst to predict the size of the system needed by looking at amount of data that will be required to handle.
        • Disadvantages
          • Very expensive as the Analyst will need to be paid for time spent looking at documentation
          • Time consuming to look through all of the existing documents
          • Time could be wasted in existing documentation which is not relevant to the new system.
  8. Explain Design stage.
    • Once there is a clear list of requirements for the new system, it is time to design how it will look and work.  The design for the new system have a lot of thoughts to put into them to try and reduce errors from the system.
    • Following are the steps included in the design stage:
      • Designing data entry screens
      • Designing user interface layouts
      • Designing printed outputs
      • Designing screen based outputs
      • Designing structures to store data
      • Designing data validation methods
      • Designing data verification methods
  9. How to design input form?
    • Much of the data that enters a computer system needs to be typed in.  A well designed on screen input form can make this task easier and quicker.
    • On screen forms should:
      • Have all of the necessary fields
      • Have sufficient place for user input data
      • Use appropriate controls for each field
      • Have text box controls that are of the right size for the data
      • Have easy to understand instructions
      • Make good use of the screen area available
      • Different types of controls are:
        • Text box:
          • Used for normal text input
        • Buttons:
          • Used to perform an action
        • Radio buttons:
          • Used to select an option
        • Tick/Check boxes:
          • Used to select an option
        • Drop down menus:
          • Used to select an option from a list
        • Example of on screen input form:
  10. Explain the term Designing of user interface.
    • User inter contains instructions for user to input data
  11. How to design printed outputs?
    • Designing printed output is just like designing an onscreen form except that it should fit on a piece of printed paper rather than on an entire screen.
  12. How to design onscreen outputs?
    • Designing an onscreen form is similar to designing printed output.  There are number of things that the designer should:
      • Show all the necessary fields.Have a field that is of the right size for the data.
      • Have easy to understand instructions
      • Make good use of the screen area available
      • Make good use of colours and fonts to make the data clear
      • E.g., Designing a report in Microsoft Access
  13. How to define data structure?
    • A data structure is an organised collection of data.  It is a database in which data will be stored as it is being processed.  When designing a database, the system designer needs to consider:
      • The type of data being stored (e.g., number, text, date, etc).
      • The size of the data (exact field size).
      • The field names to use.
      • How many records will be needed to store.
      • The designer also needs to consider which backing storage device will be suitable to store data.
      • The designer also considers the different files and folders to store the data.
  14. What are the different validation checks?
    • Validation is a process where data is checked to see if it satisfies certain criteria when input into a computer.  For example, to see if the data falls within accepted boundaries.
    • The computer system is programmed with the list of checks that it can use to compare to the data that the user enters.  If the user tries to enter something that does not match up with the checks of the validation, the system will not accept the data.  These checks are often called ‘validation rules’.
    • Different validation techniques:
      Validation Check Description Example
      Presence check Checks that data has been entered and not missed out. If a user missed out required data (such as post code), the system does not allow them to proceed.
      Length check Checks that the correct number of characters has been entered. If a date field requires the user to enter eight digits (DD/MM/YYYY), then the user must enter all the 8 digits or else the system rejects the data entered.
      Range check Checks whether numbers lie in certain ranges. Person’s age must be within the range of > 0 and < 120.
      Limit check Checks whether data entered is above or below specified limits. A learner driver’s age must be > 17.
      Format check Checks if data entered is in specific format. Date must be entered in the format of DD/MM/YYYY.
      Data type check Checks if entered data contains invalid characters. Pure number fields such as distance, temperature, etc., ought to restrict text from being entered.
      Consistency check Checks whether data in one field is consistent with data in another field. Suppose ‘Male’ is entered in Gender field, the person’s Name cannot start with ‘Mrs.’.
  15. What is Verification and what are different methods of verification?
    • Verification is a way of making sure that data being entered into the system exactly matches the source of the data.
    • There are two methods of verification:
      • Double Entry
        • This is the method where data is entered twice by two different people.  The computer compares the two entries and lets the user know if it finds any difference.
      • Visual Check
        • This is the method where the person entering data into the computer system, carefully compares what he has entered, with the data in the original document.
  16. How to test the system ? (4th stage)
    • Once the system has been created, it needs to be tested thoroughly.  A test plan is usually written whilst the system is being developed.  The test plan will contain every single thing that needs to be tested.  For example, does the system open or close properly?  can be data be entered?  can data be saved?  when you something wrong does an error appear?  is invalid data rejected? etc.,
    • A typical test plan contains:
      • Details of what is being tested
      • The test data to use
      • What is expected to happen when test is performed.
  17. When is the system tested?
    • Tested is normally done in two stages:
      • The first phase is done by the designers and engineers usually before the system is delivered to the users.  This testing is known as alpha testing.
      • The second phase of testing is done when the system is delivered and installed.  This testing is known as beta testing.
  18. What are the testing criteria?
    • There are three criteria for testing:
      • Normal data values
        • This is data that could be normally entered in system.  The system should accept it, process it and we can check the results that are output to make sure they are correct.  For example, in the range of 1-20,6,7,19,18,15 are normal data values.
      • Extreme data values
    • Extreme values are normal data values.  However, the values are to be at the absolute limits of the normal range.  Extreme values are used in testing to make sure that all normal values will be accepted and processed correctly.  For example, in the range of 1-20, ‘1’ and ’20’ are the extreme data values.
      • Abnormal data values
        • This is data that should not normally be accepted by the system.  The values are invalid, hence the system should reject any abnormal values.  Abnormal values are used in testing to make sure that invalid data does not break the system.
  19. What is documentation and what are the types of documentation?
    • Documentation is a list of instructions to use the system.
    • There are two types of documentation:
      • User Documentation
        • The user documentation is intended to help the user of the system.
        • The users are usually non-technical people who do not need to know how the system works.  They just need to know how to use the system.  User documentation usually includes:
        • List of minimum hardware and software required to use the system.
        • How to start and stop the system.
        • How to use the features of the system.
        • Examples of inputs and outputs.
        • Explanation of any error messages that might be shown.
        • A troubleshooting guide.
      • Technical Documentation
        • The technical documentation is intended to help the maintainers of the system (the people, who need to keep the system work smoothly).
        • The maintainers are usually technical people, who need to know exactly how the system works.
        • Technical documentation usually includes:
          • Details of the hardware and software required for the system.
          • Details of data structures (data type, field name, etc).
          • Details of expected inputs.
          • Details of validation checks.
          • Details of how data is processed.
          • Diagrams showing how data moves through the system.
          • Flow charts describing how the system works.
  20. What is implementation and what are the methods of implementation?
    • There are four methods of implementation:
      • Direct changeover
      • Parallel running
      • Phased implementation
      • Pilot running
      • Direct Changeover
        • In this method, old system is stopped completely and the new system is started.  All of the data that used to be input into the old system, now goes into the new system.
        • Advantages
          • Takes minimum time and effect.
          • Faster way of implementation.
          • We only have to pay, one set of workers who are working on the new method.
          • The new system is up and is run immediately.
        • Disadvantages
          • If the new system fails, there is no backup system, hence data can be lost.
          • All the staff need to be trained before the change, which may be hard to plan.
      • Parallel Running
        • In this method, the new system is started, but the old system is kept running simultaneously for a while.  All of the data that is input into the old system, is also input into the new system.
        • The old system is run alongside the new system for a period of time, until, all the people involved with the new system are happy as it is working as desired.
        • The old system is then switched off and all the work is done entirely in the new system.
        • Advantages
          • If anything goes wrong with the new system, the old system will act as a backup.
          • The ‘outputs’ from the old and new system can be compared to check that the new system is running correctly or not.
          • It allows time for the staff to be trained gradually.
          • If the new system fails, then no data or information is lost.
        • Disadvantages
        • Entering  data into two systems and running two systems together makes a lot of extra time and efforts.
        • It is very expensive as we need to pay for both the staff monitoring the system.
      • Phased Implementation
        • In this method, the new system is introduced in phases i.e., step by step, gradually replacing parts of the old system until, eventually the new system has taken over.
        • Advantages
          • Allows user to gradually get used to the new system.
          • Staff training can be done in stages.
          • If the new system fails, you only need to go back to the latest phase and do not have to review the whole system.
          • Only need to pay for the work to be done once.
        • Disadvantages
          • If a part of the new system fails, there is no backup system, so data can be lost.
          • It can take long time before the whole system is implemented.
          • There is a cost in evaluating each phase, before implementing the rest.
          • It is only suitable for systems consisting of separate modules.
      • Pilot Running
        • In this method, the new system is first of all, piloted (trial run) in one part of the business or organisation.  For example, in just one department or section.  Once the pilot system is running successfully, the new system is introduced to all the parts of the organisation.
        • Advantages
          • All features of the new system can be fully run on trial.
          • If something goes wrong with the new system, only one part of the organisation is affected.
          • The staff who were part of the the pilot system, can help to train the other staff.
          • There is plenty of time available to train the staff.
          • The implementation is on a smaller and more manageable scale.
      • Disadvantages
        • For the department working on the pilot, there is no backup system if it malfunctions.
        • It can take a long time to implement the system across the whole organisation.
        • If the system fails in one of the sections, data can be lost.
  21. What is Evaluation?
    • Evaluation is the stage where the system is completed with the objects which was set by the Analysts in the analysis stage.
    • The output from the old and new system can be compared.
    • It is measured on the basis of objectives and the system is considered to be a success if the objectives are met.
  22. How to evaluate the system?
    • The System Analyst will use a number of techniques to evaluate the system:
      • Checks against the requirements of the new system.
      • Checks the users’ responses such as:
        • Do they like the system?
        • Does it make their work easier?  etc.,
      • To evaluate the system the Analyst will:
        • Compare the final solution with the original requirements.
        • Identify any limitations in the system.
        • Identify any necessary improvements that need to be made.
        • Evaluate the users responses using the system.
        • Compare the results from the new system, with the old system.
        • Compare the performance of the new system with the old system.
        • Measure the time taken to complete the task, comparing old with new.
        • Interview users to gather responses about how well the new system works.
        • Seeing if cost efficiencies have been made.

***This is the end of this guide. Hope you enjoyed it! Thanks for using www.igcsepro.org! We hope you will give us a chance to serve you again! Thank you!***

  • Shrikant Dhamale

    Thanks but try to add up the chapter for Biology like Homeostasis
    Thanks love u guyz

    • IGCSE Pro

      Thanks you for the appreciation. We will be working on your suggestion.

  • Shrikant Dhamale

    Is this official Cambridge university site