11.1.2.5 explain the difference between the terms verification and validation
Validation & Verification
Validation
Validation is an automatic computer check to make sure that the entered data meets the requirements.
Examples
Validation methods
Validation methods
How it works
Example usage
Check digit
one or several digits in a code are used to check the other digits are correct
algorithm Luna checks the last digit in the credit card,
bar code readers in supermarkets use check digits
Format check
checks the data is in the right format
a motorbike number in Kazakhstan is in the form NN NN LL where L is any letter and N is any number
Length check
checks the data isn't too short or too long
a password that needs to be eight letters long
Lookup table/ Lookup check
looks up acceptable values in a table
when entering a social network, it searches the database for an existing username,
there are only seven possible days of the week
Presence check
checks that data has been entered into a field
in most databases, a key field cannot be left blank
Range check
checks that a value falls within the specified range
number of hours worked must be less than 50 and more than 0
Spell check
looks up words in a dictionary
when word processing
Character check
When a field has to contain a specific character or type of character.
an e-mail address should contain an “@” sign
Type check
when a field has be of a certain data type
integer, float/real
Verification
Verification is performed to ensure that the data entered exactly maches the original data / source data .
Verification methods:
1. Entering the data twice (Double entry)
Think about when you choose a new password, you have to type it in twice. This lets the computer check if you have typed it exactly the same both times and not made a mistake. It verifies that the first version is correct by matching it against the second version. Whilst this can help to identify many mistakes, it is not ideal for large amounts of data.
It would take a person a lot of time to enter the data twice.
They could enter the same mistake twice so it wouldn't get picked up.
You would end up with two copies of the data.
Examples
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2 Checking the data on the screen against the original paper document (Proofreading data or Visual check)
This saves having to enter the data twice. It can help pick up errors where data has been entered incorrectly or transposed.
However, it isn’t always that easy to keep moving your eyes back and forth between a monitor and a paper copy. Also, if you are tired or your eyes feel 'blurry' then you might miss errors.
Examples
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3 Printing out a copy of the data and comparing the printout to the original paper document.
This is probably the easiest of the verification methods because you can have both copies side by side and scan both for mistakes.However, it can be time-consuming if there is a large amount of data to check and if you do it too quickly, mistakes could be overlooked.
Examples
Question 1. Explain what is meant by data validation. (Marks: 3) Answer:
data checked by computer/software (1), at time of entry (1), that it falls within limits/is reasonable/acceptable (1)
Question 2. Explain how a range check could be used to validate the reference number. (Marks: 2) Answer:
date of birth part can be checked (1), to ensure that it is a possible date (1)
Question 3. What is the name of the extra digit at the end of the reference number? (Marks: 2) Answer:
check digit (1)
Question 4. Explain how the extra digit at the end of the reference number can help to reduce errors. (Marks: 3) Answer:
arrived at by calculation (1), when entered again - calculation repeated (1), if not the same (1), the error reported (1), any key error likely to be picked up (1) - any three points
Question 5. Describe one difference between data validation and data verification. (Marks: 1) Answer:
verification is checking that the data input is the same as the source data and validation is checking if it meets requirements/format (1)
Question 6. Give one example of data validation and one example of data verification for an authorization process. (Marks: 2)Answer:
Example of data validation:
At least 8 symbols for password (1)
Password contains upper case, lower case letters, digits, symbols (1)
Email contains @ and (.) (1)
Password must not contain space / any specific symbols / Cyrillic letters (1)