You have a relatively new employee or independent contractor working for you. You've done training, enlisted a mentor to help this person and spent countless hours advising her on best practices. Yet there are still persistent deficiencies that leave you dissatisfied with her work.

When do you pull the plug and say, "Goodbye. This isn't working out."? When do you admit that more training isn't going to solve the problems?

Here are four signs that your employee isn't going to perform to your expectations — ever:

1. Never accepts responsibility

Your employee refuses to accept responsibility for her mistakes. When you correct her, the answer is a quick "It was crazy busy around here," or "I did do it right, but there was something wrong with the computer," or "I would have caught my error before you noticed it."

Refusing to accept responsibility is a character defect, not a training problem. If she's an adult and hasn't learned yet to "fess up" to her mistakes, she's not going to. And if she can't admit that she's making mistakes, then it's not possible for her to learn from them. Goodbye.

2. Makes the same mistakes over and over

She consistently makes the same mistakes, whether due to inattention or sloppiness. She says she's "trying hard," but nevertheless, you see the same errors over and over — not getting accurate legal names before ticket-issuance, or booking the wrong airport code, or booking the wrong room type for the number in the party. On and on.

What does "trying hard" mean anyway? Either you double-check legal names, for example, or you don't — there's no such thing as "trying hard." This type of person is an expert in dodging expectations while playing the put-upon victim for being asked to live up to standards. See ya.

3. Foments dissent

She may delight in spreading gossip or fabricating stories with an innocent smile, just to agitate the camaraderie in the agency and create some drama with her in a starring role. Despite the wide-eyed, pseudo-innocence, this type of staffer will cost you dearly in terms of lost morale and group productivity.

This kind of devious behavior is not something that can be battled by more training. Therapy perhaps, but not training. Not working out — so long.

4. Costs you money

Either errors of omission or commission with her clients end up costing you refunds or loss of brand image. She's promised what neither she nor your agency can deliver, leaving a wake of dissatisfied customers. Or she's neglected something critical, like making a payment on time and losing a reservation.

Everyone makes the occasional mistake — we're human. But when her actions consistently cost you money, she's a liability, not an asset. Good bye.

The point is, if you continue to invest more of your agency's resources into training long after it's apparent that lack of training is not the problem, you're simply throwing good money after bad, like the poor investment that it is. You won't recoup your losses by investing more in these types of people, so cut your losses and move on.

Next time you're interviewing a staff applicant, structure your interview with potential scenarios to weed out these kinds of people before you introduce them into your group. The best time to cut your losses is to not have losses at all.