Input controls rate necessary to ensure the accuracy of input data otherwise the output may not be accurate. No matter how sophisticated your input hardware is and how well thought out your input methods are you still run the risk of generating inaccurate or even useless information. The completeness and accuracy of information produces by a computer system depend to a great extent on how much care was taken in capturing the raw data that served as input to the processing procedures an old computer related saying summarizes this point garbage in garbage out (GIGO). if you the-user-input incomplete and inaccurate (Garbage out). How do you ensure that input data is accurate and complete?
Input controls include a combination of manual and computer cased control procedures designed to ensure that all input data has been accurately put into computer-usable form. A variety of control techniques can be used depending in the design of the computer system and the nature of the pro build them into systems.
How important are input controls? Consider the modest-living couple who got a phone bill or a local stores invoice for $450000 and spent months trying to convince the company it was a mistake. The customer service personal and the data processing staff were probably trying to identify the glitch in the input control procedures. The computer doesn’t make mistakes the people who input data and monitor input procedures do. Even software writers are not infallible. Without input controls mistakes mighty are impossible to detect or correct. Imagine the consequences this could have at the level of international trade politics, and military activities. Of course input controls are not the only controls involving data accurately, completeness and security.