25o words

One control that is applicable for almost any system is "enter data close to the originating source".  A customer entering a purchase into an online sales system (such as at Amazon.com) is an excellent example of this control.

In about 250 words (i.e. one page double spaced), describe the details of why this process produces fewer errors than a process where the sales clerk manually writes down the customer's order.  Be sure to include validity, completeness, and accuracy in your answer.