Additional sickness days and other absences
It is not uncommon for poor hires to take higher than average numbers of sickness days in addition to a variety of other absences. This will almost certainly have a knock-on effect across your team, with the added pressure most keenly felt by their closest colleagues.
Let's say that your mis-hire works in close collaboration with four other team members and is regularly absent. Those four colleagues will be required to take on additional tasks by way of coverage. This will either impact the volume of work they are able to complete, the quality of said work, or both.
These very same team members might be forced to work additional hours to mitigate the impact of their under-performing colleague. In turn, this will contribute to additional levels of fatigue and stress. Sadly, this situation may very well be temporary; if these employees feel underappreciated, they may soon start to consider their own options which could result in your business losing some of its most valuable and experienced team members.
THE COST OF A POOR HIRE ON TEAM-WIDE PRODUCTIVITY LEVELS
The co-workers and supervisors of a poor hire will have almost invariably invested a considerable amount of time into bringing them up to speed on the role and tasks at hand. With the best will in the world, there will be a learning curve that each new employee must navigate until they become a fully productive member of the team. If that individual is a good fit for the company, this investment of time and energy from co-workers, supervisors and management teams will pay off. Not so with a poor hire, resulting in wasted time, investment and, most perniciously, an adverse effect on morale.
In practice, this can impact team morale in several ways. Not only have they invested physical and emotional energy into a co-worker who is no longer part of their team, but they will also recognise that the whole process will need to be repeated when a new hire is brought in as a replacement.
Perhaps more than once.
Whilst managers and hiring teams may want to get the now-vacant role filled as quickly as possible, it is essential to recognise that hiring in haste is often a sure-fire way to employ yet another individual who is not entirely suited to the role.