- Data source error
- The given data already has errors
- Transcription error
- Mainly typo mistakes
- Can be made by Human / OCR software.
- Transposition error
- Mainly typo mistakes
- Most of the time made by human
- Difference between transcription and transposition error
- Transcription error is when the whole thing is wrong (wild pig -> wood pig)
- Transpostion error is when the characters is misplaced (wild pig -> wlid pig)
All methods below are used to ensure that data are valid.
- Field presence checks
- Checks if field is being filled in
- Length checks
- Checks length of input
- Phone numbers have 8 digits, can check if phone number entry has 8 digits
- Range check
- Check range of input
- Age is <150, can check if age is valid by checking if value is smaller than 150
- Fixed value check
- Check if value of input matches prefix
- Sex is usually M/F, can check if sex is legit
- Format check
- Check if format of input matches prefix
- ID Card has special format, can check if ID number is legit
- Type check
- Check if data type is correct
- Student Grades should be characters not numbers, can check if there is error in input
- Check digit
- Check if numeric data has the same length
- Same as length checks
- In order to reduce data errors:
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Enter data twice
- Same person enter data twice
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Double entry
- Different person enter data twice
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Entering data twice can reduce error count as it is very rare that the two inputs will have the same error.
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