Monday 7 January 2013

Documents used for information processing

Source documents
These are the original documents that their data is entered/inputted into a computer system. Once the data has been entered, the document should be filled away safely and not thrown away. This is because the data may have to be checked.
Human-readable documents
These are forms/documents that are filled by hand before their data is enter into a computer system. These documents can be read by humans. For example a immigration form or job application form.
Machine-readable documents
These are documents that instead of writing, the form is marked in some (special) way and the document is passed through a scanner where the scanner identifies the marks. OMR (Optical Mark Reader/Recognition), MICR (Magnetic Ink Character Reader/Recognition), OCR (Optical Character Reader/Recognition) are various technologies that allow machine readable documents to be read. For example CXC multiple choice answer sheet and bar code on food products.
Turnaround documents
These forms/documents are printed from the computer system with particular information for the purpose of retrieving addition or new information (either from customer, employees, etc...) to be reentered into the computer to update the original information

Verification & Validation of data

Data Verification
This is a process carried out by humans. It is the process of correcting and/or back checking information (either written or typed) for written errors or typing errors. For example the act of reading back from the screen information and checking to verify that the information is inputted correctly. Errors made by humans are:
  1. Typographical error - Typing error when we hit the wrong key (a typo)
  2. Transpositional error - Typing error when we enter numbers in incorrect order
Various data verification checks are:
  1. Double Entry - The user is prompt for double entry to minimize chance of error. For example when creating a new email you would are prompt to enter your new password twice.
  2. Proof Reading - The user reread information while checking for errors.
Data Validation
Is an automatic process carried out by software in a computer system to ensure that the inputted data, is inputted in the appropriate format, range and/or type. Various data validation checks are:
  1. Range check - Checks whether numerical data is inputted within expected limits. For example entering 13 as a month when there is only 12 months.
  2. Data type checks - Checks whether inputted data corresponds to the appropriate data type.
  3. Check digit check
  4. Length check
Now, think about certain scenarios involving entering information into a information system and create verification and validation checks to minimize human error.