I suspect that the real figure is a bit higher, but still, the poor performer problem is not nearly as bad as most Americans think. Aside from inefficiency, there are four huge costs of the federal government's inability to kick turkeys off the farm. First, non-performers themselves never get the message that they have to shape up or ship out and never get the chance for a new start. Instead, they often use the system to pursue old grudges for years. Third, the low performance problem undermines the image and self-image of the bureaucracy.
Business people have no tenure and look down on their government cousins who do.
This makes the officer corps, at least at higher levels, a turkey-free zone, giving the brass a certain swagger in their dealings with their protected cousins in the civil service. Most important, a tenured civil service undermines the legitimacy of the bureaucracy in the eyes of the public. After all, very few voters have tenure, so it is hard to tell citizens why their public servants cannot be fired. It is not surprising that college professors, public school teachers, and government bureaucrats have all come under attack in recent years. Originally, the federal merit system was set up in 1884 to keep political parties from using government jobs to reward supporters.