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Q: What is data validity?
A:
Data validity is the correctness and reasonablenesss of data.
Reasonableness of data means that, for example, account numbers falling within a range, numeric data being all digits,
dates having a valid month, day and year, and spelling of proper names.
Data validity errors are probably the most common, and most difficult to detect (data-related) errors.
What causes data validity errors?
Data validity errors are usually caused by incorrect data entries,
when a large volume of data is entered in a short period of time.
For example, a data entry operator enters 12/25/2010 as 13/25/2010, by mistake, and this data is therefore invalid.
How can you reduce data validity errors? You can use one of the following two, simple field validation techniques.
Technique 1: If the date field in a database uses the MM/DD/YYYY format,
then you can use a program with the following two data validation rules: "MM" should not exceed "12", and "DD" should not exceed "31".
Technique 2: If the original figures do not seem to match the ones in the database,
then you can use a program to validate data fields.
You can compare the sum of the numbers in the database data field to the original sum of numbers from the source.
If there is a difference between the two figures, it is an indication of an error in at least one data element.
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