Define each of the following input controls and give an example of how they may be used:

Question

a. Missing data check
b. Numeric/alphabetic data check
c. Limit check
d. Range check
e. Reasonableness check
f. Validity check

Answer 1

Missing data check is useful because some programming languages are restrictive as to the justification (right or left) of data within the field. If data are not properly justified or if a character is missing (has been replaced with a blank), the value in the field will be improperly processed. For example, the presence of blanks in a numeric data field may cause a system failure. When the control routine detects a blank where it expects to see a data value, the error is flagged.

A numeric-alphabetic check control identifies when data in a particular field are in the wrong form. For example, a customer's account balance should not contain alphabetic data and the presence of it will cause a data processing error. Therefore, if alphabetic data are detected, the error record flag is set.

Limit checks are used to identify field values that exceed an authorized limit. For example, assume the firm's policy is that no employee works more than 44 hours per week. The payroll system input control program can test the hours-worked field in the weekly payroll records for values greater than 44.

Range checks exit when data have upper and lower limits to their acceptable values. For example, if the range of pay rates for hourly employees in a firm is between 8 and 20 dollars, this control can examine the pay rate field of all payroll records to ensure that they fall within this range.

A reasonableness check determines if a value in one field, which has already passed a limit check and a range check, is reasonable when considered along with data in other fields of the record. For example, assume that an employee's pay rate of 18 dollars per hour falls within an acceptable range. This rate is excessive, however, when compared to the employee's job skill code of 693; employees in this skill class should not earn more than 12 dollars per hour.

A validity check compares actual field values against known acceptable values. For example, this control may be used to verify such things as valid vendor codes, state abbreviations, or employee job skill codes. If the value in the field does not match one of the acceptable values, the record is flagged as an error.