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Data Control Methods: Validation vs. Verification

Understand and apply methods to ensure data accuracy and completeness in data input processes. Learn about preventing errors and best practices through validation and verification techniques.

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Data Control Methods: Validation vs. Verification

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  1. Chapter 3 Data Control

  2. Data Control • Ensure the Accurate and Complete data is entering into the data processing system.

  3. Sources of error • Data Collection errors • Enter wrong information onto the source documents. • E.g.. Poor handwriting • Data Preparation errors • Transcription error • Data on the source document are copied incorrectly. • Data Input errors • Typing error

  4. Preventive Measure: • Data Verification • Data Validation

  5. Data Verification • Checking the accuracy of data has been copied from one medium to another. • Usually takes place at the DATA PREPARATION or DATA INPUT stage.

  6. Verification Process: • It involves two operators to type the same set of data independently. • First operator types in the data. • Second operator re-enters all the data. • A computer program compares both input. Alert the operator if Discrepancies occurs.

  7. Data Validation • Ensure data is valid and acceptable for data processing. • Done by validation program.

  8. Data Validation Methods • Presence check • Range check • Data type check • Consistency check • Control total(batch total) • Hash total • Check digit

  9. Data Validation Method • Presence Check • Ensure the data are present. • Range Check • Ensure data lie within a certain range. • Data type Check • Ensure data type is correct.

  10. Data Validation • Check Digit is an extra digit appended to a code consisting of a series of numbers or characters. • Detect errors arising from transcription.

  11. Modulo 11 Check 53622 / 11 = 4874 … 8 Remainder = 8 which equals to the check digit. The input data is correct. 53622 (8) Check digit

  12. 53622 (8) 53627(8) Original Input Modulo 11 Check 53627 / 11 = 4875 … 2 Remainder = 2 which NOT equals to the check digit(8) .The input data is INCORRECT. Check digit

  13. 536228 (0) 526328(0) Input Original Modulo 11 Check 526328 / 11 = 47848 … 0 Remainder = 0 which equals to the check digit(0).The input data is also considered as CORRECT but in fact it is incorrect. Check digit

  14. X 2 = 4 X 3 = 6 X 4 = 24 X 5 = 15 X 6 = 30 79 Weighted modulo 11 check • A weight is given to each digit. 5 3 6 2 2 (9) 11 = 7, remainder=2 Subtract the remainder from 11 to get the check digit, 11 – 2 = 9

  15. X 1 = 9 X 2 = 4 X 3 = 6 X 4 = 24 X 5 = 15 X 6 = 30 88 Weighted modulo 11 check for Account Number • A weight is given to each digit. 5 3 6 2 2 (9) 11 = 8, remainder=0 So, the account number is valid.

  16. X 2 = 4 X 3 = 3 X 4 = 28 11 X 5 = 15 X 6 = 30 X 7 = 28 X 8 = 208 Weighted modulo 11 check for ID card number • A weight is given to each digit. Check digit = 11 – 8 = 3 Z 4 5 3 7 1 2 (3) A = 1 B = 2 C = 3 . . . Z = 26 308 …8 28

  17. Differences between Data Validation and Data Verification

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