Why not fire them and hire someone whose performance is acceptable?
Most federal employees have their performance rated annually, commonly on four- or five-level scales in which “unacceptable,” or a similar term, is the lowest rating. Those ratings are used in decisions such as promotions and awards, but annual raises typically are paid across the board regardless of performance ratings.
“Currently, all federal civilian employees, no matter how they are rated on their performance, receive the annual nationwide adjustment in January of each year,” a House committee report on the defense bill said. “Federal civilian employees who are rated as ‘below satisfactory’ still receive an increase in salary despite the fact that they are underperforming. An incentive is necessary to entice these employees to improve their job performance.”