In the ground-breaking book Electronic Performance Support Systems published in 1991, Gloria Gery, defined EPSS as:

"an integrated electronic environment that is available to and easily accessible by each employee and is structured to provide immediate, individualized on-line access to the full range of information, software, guidance, advice and assistance, data, images, tools, and assessment and monitoring systems to permit job performance with minimal support and intervention by others."

An electronic performance support system can also be described as any computer software program or component that improves employee performance by

1. reducing the complexity or number of steps required to perform a task,

2. providing the performance information an employee needs to perform a task, or

3. providing a decision support system that enables an employee to identify the action that is appropriate for a particular set of conditions.
   

Electronic Performance Support Systems can help an organization to reduce the cost of training staff while increasing productivity and performance. It can empower an employee to perform tasks with a minimum amount of external intervention or training. By using this type of system an employee, especially a new employee, will not only be able to complete their work more quickly and accurately, but as a secondary benefit they will also learn more about their job and their employer's business.