First, people tend to use or not use an application to the extent they believe it will help them perform their job better. We refer to this first variable as perceived usefulness. Second, even if potential users believe that a given application is useful, they may, at the same time, believe that the systems is too hard to use and that the performance benefits of usage are outweighed by the effort of using the application. That is, in addition to usefulness, usage is theorized to be influenced by perceived ease of use.