Editor's note: Inc.com columnist Alison Green answers questions about workplace and management issues -- everything from how to deal with a micromanaging boss to how to talk to someone on your team about body odor.

A reader writes:

As managers, we all have had to interview a person where you know five minutes in that there is zero chance you are going to proceed with them. Sometimes it's a lack of interest on their end, inability to answer clearly or professionally, or maybe just being woefully unqualified. Is there a nice way to cut bait?

I like to treat people interviewing with respect and dignity, and always try to be as hospitable as possible. However, carrying someone through a conversation for 25-30 minutes who you know isn't a fit is just a waste of their time and yours.

How do you politely say, "Thanks, that'll be all?"

This is one of the huge advantages of doing phone screens before bringing people in for in-person interviews. You can't eliminate this problem altogether, but you can cut way down on it.

But you'll still run into it on occasion. There are candidates who seem great on paper and who do pretty well when you talk through the basics on the phone, but when you bring them in, they have an obvious deal-breaker pretty early on. Or, you might work in an organization that strictly dictates what hiring procedures you're allowed to use and for unknown reasons doesn't phone-screen candidates first (or that has someone inept selecting candidates to bring in to interview with you). If that's the case, you should push back on those practices.

In any case, whether or not there's a polite way to cut the interview short depends on what the candidate's specific deal-breaker is.

If the reason is something that you can easily articulate, it makes sense to do that. For instance, let's say that you thought from a candidate's resume that she had pretty significant experience in curriculum design, but when you start probing into the details of it, you discover that she has only delivered trainings that other people have designed. You might say something like this: "For this role, we're really looking for fairly deep experience with curriculum design, so it sounds like it's not quite the right fit. I'm sorry we didn't catch that earlier. I so appreciate you taking the time to come in, and I'd be glad to keep you in mind if we have something in the future that's more focused on curriculum delivery." (And again, ideally you'd ask the right questions to catch this in a phone interview, but sometimes something weird like this slips through.)

You can use a softer version of this too, airing your concerns but leaving it more in the candidate's court to decide whether to continue talking. For instance, if the candidate makes it clear that she adores old-school PR and you really need someone who's passionate about social media, you could say, "This role is heavily focused on social media and doesn't involve much traditional PR. Knowing that, does it make sense to continue talking, or are you really looking for something with a different focus?"

But often at this stage, instant deal-breakers are likely to be things that you don't really want to articulate on the spot -- for instance, that the person's answers are vague and don't show any insight, or his appearance is so horridly unkempt that you could never put him in front of the audiences he would need to work with, or she's oddly combative, or any other of the myriad interpersonal reasons that are a lot harder to explain to someone's face than an experience mismatch.

When that's the case, I'd say the best thing to do is to continue on with the interview, but without spending as much time as you'd generally spend with a strong candidate. For instance, if you'd normally talk for an hour, you can probably wrap up in 30-40 minutes by asking fewer questions (cutting out the ones designed for lengthier, more in-depth discussion). It might feel like a waste of time, but it's an investment in good will -- because after all, this is someone who set aside to come in and talk with you, probably spent time preparing beforehand, might have taken time off work, etc. It's a recognition of that.

And actually, one way you can spend that time is in probing more into the areas where you think they're lacking. If you're mentally rejecting them because they seem weak in X, make it your job to test that belief. If what you hear confirms your original impression, well, you'll know you were right. But for all you know, you might discover that the story is slightly different than what you thought at first. Or even if not, you might learn enough about them to think of them for a different role in the future, or to realize that they really should contact your colleague in another team who's looking for someone just like them.

Want to submit a question of your own? Send it to alison@askamanager.org.