In IB Computer Science, students are often asked to explain how systems ensure that data is accurate and reliable. This is done using data validation and data verification. Although these terms sound similar, they solve different problems, and confusing them is a common reason students lose marks.
IB examiners expect students to clearly distinguish between checking data makes sense and checking data was entered correctly.
Why Data Checking Matters
Modern systems rely heavily on user input.
If incorrect data is entered:
- Databases become unreliable
- Decisions may be wrong
- Systems may fail or behave unpredictably
Validation and verification help reduce these risks, but they work in different ways.
What Is Data Validation?
Data validation checks whether data is:
- Reasonable
- Sensible
- Within expected rules
Validation does not check whether the data is correct in the real world — it checks whether it follows predefined rules.
In IB terms, validation checks data quality, not data truth.
Common Data Validation Checks
IB students should be able to explain common validation methods, including:
- Range check
Ensures data falls within acceptable limits - Type check
Ensures data is the correct data type - Length check
Ensures data is not too long or too short
