Every company has its "bad apple" employees, who undermine their coworkers' efforts through apathy, incompetence or uncivil behavior. Instead of showing an under-performing employee the door, however, employers may shuffle him from job to job, or simply ignore the situation. Without a check on their behavior, poor employees quickly become a drain on company budgets, coworkers' morale and supervisors' time -- which makes the cost of keeping them around extremely steep.

Diminished Productivity

Leaving bad apples to their own devices also diminishes productivity, because negative interactions carry greater influence on people than positive ones. Social researchers have established a link between poor productivity and exposure to inappropriate workplace behaviors, such as slacking, lack of respect, or voicing depressive, pessimistic attitudes. Even the inclusion of one such coworker can be enough to bring down a team's overall productivity by 30 or 40 percent, "The Wall Street Journal" reported in March 2013.

High Turnover

Organizations that don't intervene against poor employees also risk losing their brightest stars. When top performers see mediocrity being tolerated, turnover is likely to accelerate, according to Francie Dalton, a career consultant interviewed for "HR Magazine." Underachieving employees are more likely to stick around, however, because they realize that nobody will hold them accountable. A company stuck with poorly performing employees is less likely to operate well than one that weeds out such workers.

Lower Morale

Poor performers drag down morale. Employees who aren't interested in their jobs anymore will inspire coworkers to question their purpose, too, as a November 2012 survey of chief financial officers by the Robert Half International staffing firm suggests. For example, 95 percent of the CFOs believed that a bad hiring decision at least "somewhat" affected their team's morale. Thirty-five percent of the CFOs also agreed that a poor hire had "greatly" impacted morale.

Management Stress

Dealing with a poor performer is stressful for managers, too. Lean budgets may prompt supervisors to give the worker less demanding tasks, or try coaxing him into improving his performance. Overall, supervisors participating in the Robert Half survey estimated that they spent roughly 17 hours per week -- or one full work day -- managing poor employees, who require more supervision. However, these problems only distract managers from day-to-day operations, which forces coworkers to pick up the slack.