Transcript data input

Chapter 3
Data Control
Data Control

Ensure the Accurate and Complete data
is entering into the data processing
system.
Sources of error
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Data Collection errors
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Enter wrong information onto the source
documents.
E.g.. Poor handwriting
Data Preparation errors
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Transcription error
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Data on the source document are copied incorrectly.
Data Input errors
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Typing error
Preventive Measure:
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Data Verification
Data Validation
Data Verification

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Checking the accuracy of data has been
copied from one medium to another.
Usually takes place at the DATA
PREPARATION or DATA INPUT stage.
Verification Process:

It involves two operators to type the
same set of data independently.
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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.
Data Validation


Ensure data is valid and acceptable for
data processing.
Done by validation program.
Data Validation Methods
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Presence check
Range check
Data type check
Consistency check
Control total(batch total)
Hash total
Check digit
Data Validation Method
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Presence Check
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Range Check
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Ensure the data are present.
Ensure data lie within a certain range.
Data type Check
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Ensure data type is correct.
Data Validation

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Check Digit is an extra digit appended
to a code consisting of a series of
numbers or characters.
Detect errors arising from transcription.
Modulo 11 Check
53622 (8)
Check digit
53622 / 11 = 4874 … 8
Remainder = 8 which equals to the check digit.
The input data is correct.
Modulo 11 Check
Original
53622 (8)
53627(8)
Input
Check digit
53627 / 11 = 4875 … 2
Remainder = 2 which NOT equals to the check
digit(8) .The input data is INCORRECT.
Modulo 11 Check
Original
536228 (0)
526328(0)
Input
Check digit
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.
Weighted modulo 11 check

A weight is given to each digit.
53622
(9)
X2=4
X3=6
X 4 = 24
X 5 = 15
X 6 = 30

79 11 = 7, remainder=2
Subtract the remainder from 11 to get the check digit, 11 – 2 = 9
Weighted modulo 11 check for Account Number

A weight is given to each digit.
53622
(9)
X1=9
X2=4
X3=6
X 4 = 24
X 5 = 15
X 6 = 30
88 11 = 8, remainder=0
So, the account number is valid.

Weighted modulo 11 check for ID card number
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A=1
B=2
C=3
.
.
.
Z = 26
A weight is given to each digit.
Z 4 5 3 7 1 2 (3)
X2=4
X3=3
X 4 = 28
X 5 = 15
X 6 = 30
X 7 = 28
X 8 = 208
Check digit
= 11 – 8
=3
11 308 …8
28
Differences between Data Validation and Data Verification
Data Verification
Data Validation
Checking data that have Check validity of data
been copied from one
before they are
medium to another.
processed.
Include Invalid data
Exclude Invalid data
Takes place at data
preparation stage.
Takes place at data
input stage (prior to
processing).
after data verification.
after data validation.