Input Controls

Assignment 3: Input Controls and Restricting User Interface

CIS210 – System Analysis and Development

August 10, 2012,

INPUT CONTROLS

No matter how data enters an information system, the quality of the output is only as good as the quality of the input. When developing or purchasing a new system or application, it is important that the system or application has adequate input controls. “Input controls ensure the complete and accurate recording of authorized transactions by only authorized users; identify rejected, suspended, and duplicate items; and ensure resubmission of rejected and suspended items (Understanding Internal Control).” These controls are critical because a large number of errors in computer systems are the results of input errors. “Input controls will ensure that data is accurately processed through the application and that no data is added, lost, or altered during processing (Hall, 2011).” There are several types of input controls for an input design such as check digits, reasonableness checks, validity checks, and batch total control. In this paper, I will discuss these input controls more in detail.

When human beings use numbers - whether keying them into computers, dialing them on telephones, or reading them and telling them to others; they tend to make certain kinds of mistakes such as entering an incorrect digit, changing the order of successive digits, or adding additional digits. These types of simple mistakes are known as transposition and transcription errors. Check digits are an input control method used for detection these types of errors. “Check digits are numbers produced by mathematical calculations performed on input data such as account numbers. The calculation confirms the accuracy of input by verifying the calculated number against other data in the input data, typically the final digit (FFIEC IT Examination Handbook InfoBase).” For example, a sales order for customer 957345 that is transposed into...