Information Technology IT – 1 Data processing and information | e-Consult
1 Data processing and information (1 questions)
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Here are three verification methods:
- Visual Checking: This involves manually reviewing the entered data against the original source document (e.g., a paper form or a scanned image). The clerk compares each field in the database entry with the corresponding information on the source document.
- How it works: The clerk systematically goes through each record, comparing values.
- Errors detected: This is effective for detecting simple transcription errors (e.g., a transposed number, a misspelled name). It's also good for identifying missing data if a field is absent from the source.
- Limitations: It's time-consuming and prone to human error, especially with large datasets. It's also not effective for detecting errors in data format (e.g., a date entered in the wrong format).
- Double Entry: This involves having a second person independently enter the same data into the database. The two entries are then compared.
- How it works: Two individuals enter the data separately. A reconciliation process is used to identify discrepancies.
- Errors detected: This is highly effective for detecting a wide range of errors, including transcription errors, data entry mistakes, and even errors introduced by software glitches.
- Limitations: It's expensive (requires two people) and time-consuming. It doesn't detect errors that both individuals make identically. Requires a robust reconciliation process.
- Parity Check: This is a simple error detection technique used to verify the integrity of data transmitted or stored in a binary format. It involves adding an extra bit (the parity bit) to the data. The parity bit is set to either 0 or 1 to ensure that the total number of 1s in the data (including the parity bit) is either even (even parity) or odd (odd parity).
- How it works: A parity bit is calculated based on the data bits. The parity bit is appended to the data. Upon retrieval, the parity bit is recalculated and compared to the received parity bit. If they don't match, an error is detected.
- Errors detected: Parity checks are effective for detecting single-bit errors. They are not effective for detecting multiple-bit errors.
- Limitations: Only detects single-bit errors. Doesn't detect errors that result in an even/odd number of bit flips.