The same thing applies to marginal employees already in place. First, ask yourself, why is this person underperforming? Could his/her performance be turned around with better guidance and training? If so, it’s more cost-effective to help that person improve than to go through the expensive and time-consuming process of replacing him/her.

I’ve had two situations where I had to “fire quickly.” In one, I had promoted an employee into a new position but quickly found out that I had been snowed both as to her qualifications and her productivity. So I admitted my mistake and terminated her. In the other, I was prepared to fire an employee for underperforming, but after a further conversation, found that the problem was one of communications in both directions as far as his job specs were concerned, so we fixed that and kept him on. The CEO was astounded that I would reverse myself so quickly, but again, admitting my mistake and reversing my decision turned out to be one of the best moves I’ve ever made.

Once again you are dead on right.