Before You Go Job-Hopping...

Don't accept a new positionno matter how sweetwithout nailing down the details

I've had my job for six years, but there's little runway for me here. Last week a business acquaintance offered me a job at his company. It's not my area of expertise, and the position is a bit unclear, but it seems exciting. Do I go for it? — Anonymous, Wayne, Pa.

Does your new opportunity seem exciting—or just different? We ask because you have our alarm bells ringing. Not that we don't like exciting jobs; far from it. It's just that we've seen too many people take a new job just to get rid of the old one. That choice can work. We've all heard stories of people who owe their careers to a spontaneous switch. But in general, when it comes to managing your career, we'd have to invoke and twist that old saying: It's better to be smart than lucky.

By smart, we mean informed. Which is exactly what you aren't right now. You're just intrigued, probably because you're bored or frustrated at your current place. Maybe you work for a family business, and you've climbed as close to the top as you'll ever get. Or maybe your company isn't growing. The specifics are irrelevant. What matters is you seem poised to leap before you look. Don't—at least not until you conduct some serious due diligence.

Start with the offer itself. From where we sit, it's confounding, don't you agree? The work doesn't play to your strengths, but even more concerning, your role isn't defined. It's as if your acquaintance is saying: "We'll figure out the details after you get here." To which we say: "Run for the hills."

Look, almost nothing in management is more frustrating than being given responsibility without authority. Your new boss, whether it's your acquaintance or not, will surely want results from you soon enough. But without a clearly defined job, you're in trouble. You may not, for instance, be able to hire people or spend any real money. Your co-workers may shrug you off; who are you, anyway?

This dynamic has no better illustration than a story told by Cathie Black in her terrific business memoir, Basic Black (2007). After a year of being wooed by founder Al Neuharth, Cathie accepted the job as president of USA Today in 1983. On her first day, however, she was mortified when an ad executive approached her to announce: "I just want you to know up front, I'm not going to be reporting to you." With a sick feeling, Cathie recalls, she realized she had made a classic mistake. "I had never nailed down, in writing, the reporting structure and what my actual duties were to be." It took Cathie, who went on to become president of Hearst Magazines, months to straighten her role out at USA Today, although her long run at the paper had a happy ending.

And your new job might, too, if you get its specifics clarified before signing on. Even so, there's a second and final piece of due diligence to complete, and it concerns values. You need to make sure the opportunity dangling before you isn't alluring for the wrong reasons—namely, money and prestige.

Make no mistake. There is nothing wrong with taking a job that enhances your compensation or your reputation. But too often such jobs can come with a real cost to your less-than-immediate future, not to mention your pride and authenticity. We have a friend who grabbed an unexpected offer for its elevated title—vice-president—and $25,000 salary boost, only to end up as the fall guy for a company that was going down the tubes. Another friend, a golf pro, gave up his job at a friendly little club for the glamour of working at a fancy, big-name course. The next thing he knew, he'd gone from partner to serf, treated by members as little more than a scheduler. At the small club, his wife had been an office manager and playing member. At the big, she is working in the bag room. Yes, the pro had feared this exact outcome. But he'd let the "oohs" and "aahs" of his friends over the new job's cachet drown out the "uh-ohs" in his head.

Without doubt, the offer in front of you could turn out to be the break-through you've been dreaming of. Maybe it will replace monotony with magic. But don't leap for it without looking hard, both inside the new company for clarity and purpose and into your own heart for a sign that the change is worth its consequences.

Before it's here, it's on the Bloomberg Terminal.