2.2 Data Checking

Question 1

Define data.

Answer 1

Unprocessed facts and figures which have no meaning on their own. Data is entered into a computer and processed, and then becomes information.

Question 2

Define information.

Answer 2

Data that has been processed and is presented in a way which is meaningful to users.

Question 3

Define verification.

Answer 3

A way of ensuring that data entered into a computer has been accurately transferred from a paper-based form.

Question 4

Describe 2 methods of verification.

Answer 4

1. Double entry - Data is keyed into the computer system by 2 different operators and the computer system compares the 2 sets of data. Any mismatching data is rejected and then re-entered. This ensures data is transferred accurately and correctly.
2. Proofreading - Documents once typed are proofread to ensure that they contain correct and accurate information.

Question 5

Define validation.

Answer 5

A way of checking data to ensure that it is acceptable and sensible. Data can be checked that it is present, of the correct type, of the correct length or within the correct range.

Question 6

What is the purpose of a presence check?

Answer 6

It ensures that data has been entered into an area on a form. This check means that important data which must be entered is not omitted.

Question 7

What is the purpose of a length check?

Answer 7

It ensures that data entered is of the correct length.

Question 8

What is the purpose of a data type check?

Answer 8

It ensures that the data entered is of the correct format (Eg. numeric, text, date, Boolean, currency).

Question 9

What is an input mask?

Answer 9

An expression that helps define what type of data is allowed in a given field, eg. a postcode format.

Question 10

What does a range check ensure?

Answer 10

That data entered is within a given range.

Question 11

What is a lookup table?

Answer 11

A list of data which can be used to provide values for other data fields.

Question 12

Describe what a check digit is and how it works.

Answer 12

A check digit is a digit added to the beginning or end of a number to verify that the number entered is an authentic code. The digit is compared with the results of a calculation using the code. If the results of the calculation do not match the check digit, the code has to be input again.