can I accept a job knowing I plan to leave it in a few months?

A reader writes:

I have recently been offered a job with a company locally and have accepted it. However the hiring process a extensive background investigation is needed and will not be able to start this position until the January of 2011. I have more recently been offered a another job a couple of hours away. I would prefer to accept the position locally but I need an income that I could get from the other job a couple hours away. Is it acceptable to use this job until the other job and background investigation on done?

I get versions of this question all the time, all ultimately wanting to know:  When is it okay to take a job knowing you're likely to leave it quickly as soon as something better comes along?

First, two situations where I'll give you an immediate pass:  (1) If you're being honest with the first employer about your intent and they hire you knowing that, go for it, and (2) if this is a job or industry where high turnover is typical and routine, such as retail, call centers, and so forth, fine.

But aside from that, here are some principles that you should apply to any question along these lines:

* If you're not being candid with the employer, what will the impact be on them? In many businesses, an employee leaving after just a few months means that time, money, and other resources were wasted on training; they have to go through the time and expense of a new hiring process; and often the area your role was responsible for suffers setbacks, either minor or major. Is this a large business that can more easily absorb the impact, or a small business that will feel it much more? Is it a nonprofit that will have to divert resources away from a valuable mission to respond? Different organizations are impacted to different degrees by this, and you want to think about what the impact will be in your case.

* Are you willing to accept a possible hit to your own reputation?  It's likely that you will always be "the guy who left after we spent two months training him." You won't just burn bridges with the first organization; it may impact you other places too, because the world is fairly small. Are you willing to accept the possibility that you might be going after a job you really want some day and find that your interviewer was the co-worker who picked up the slack after you disappeared -- or knows one of those co-workers? (I know this sounds like a loaded question, but it's a genuine one. You might weigh everything and decide that, yes, you are willing to accept this. That's fine; I just want you to think it through first.)

Speaking of reputation, it's also worth asking yourself what your new employer will make of this. They may assume you're willing to do the same thing to them.

* This one is hard to quantify, but you should at least be aware that there were probably other people who really wanted that first job and would have been thrilled to get it ... and might have gotten if it the employer had known that you had secret plans to leave after a few months. Again, your call to make, but this should be part of the ethical landscape that you think about.

Now, whenever this topic comes up, someone points out that you don't owe employers any loyalty because they may fire or lay you off without notice, etc. But it's a rare employer who will hire someone planning to fire her in a couple of months, or who will hire you and then rescind the job offer when a better applicant shows up. And yes, plenty of employers treat employees badly, but it's far from true of everyone, so at least make sure you know who you're dealing with before you paint everyone with the same brush.

All that said, it's certainly true that employers make decisions based on what's in their own best interests. But the reason they don't, for instance, hire someone planning to fire her in two months, is because that's not in their best interests. It's not in their best interests to become known as an employer who does that kind of thing, or to make their current employees worry they'll do it to them. And it's not in their interests to become known as a company that treats people unfairly or callously, because they want to be able to attract and keep good people. And something similar is true for you: It's not in your own interests to get a reputation as someone who doesn't keep commitments, who cuts and runs, or who acts without integrity or concern for others -- because you want to to be able to work with good people too.

So just as employers will act in their own best interests, you should too. But you should make sure you have a really comprehensive picture of what those interests are -- and for all the reasons above, it's not as simple as "Job A is better than Job B."