12. Verification methods

Verification can be performed in a few ways:

Entering the data twice.

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 could take a person a lot of time to enter the data twice.
• They could enter the same mistake twice and so it wouldn't get picked up. 
• You would end up with two copies of the data.

Checking the data on the screen against the original paper document

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.

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.