Validation and Verification

Validation and verification are two ways to check that the data entered into a computer is correct. Data entered incorrectly is of little use.

Data verification

Verification is performed to ensure that the data entered exactly matches the original source. Verification means checking the input data with the original data to make sure that there have been no transcription errors (transcription means copying the data). The standard way to do this is to input the data twice to the computer system. The computer then checks the two data values (which should be the same) and, if they are different, the computer knows that one of the inputs is wrong. e.g. Entering password twice during sig-up. Verification methods include:

Ø  double entry

Ø  screen/visual check (proof reading)

Ø  parity check

Ø  checksum.

Validation is an automatic computer check to ensure that the data entered is sensible and reasonable. It does not check the accuracy of data.

For example, a secondary school student is likely to be aged between 11 and 16. The computer can be programmed only to accept numbers between 11 and 16. This is a range check.

However, this does not guarantee that the number typed in is correct. For example, a student's age might be 14, but if 11 is entered it will be valid but incorrect. #olevelcomputer #inqilab #cambridge