I use the term "fire in the belly" to refer to someone’s drive or motivation to achieve success. When you’re interviewing prospective employees for your business, people will often describe a "passion" for the product, technology, or tasks at hand. This is nice, but fire in the belly burns on while passion burns out. Fire in the belly is a continued drive that doesn’t ebb or flow while passion rises and falls. To find fire in the belly in a potential new employee, look for three things:

First, look for a history of drive. People with drive have had it their whole life. It’s in their DNA, and they’ve typically demonstrated it from very early on. Ask questions about their very first job. Not the one after college, but the very first thing they did for pay. Guess what: People with drive usually started working early in life and took the jobs they could get for the pay available. If they are who you’re looking for, they didn’t then and don’t now have any problem with working hard. It is what they do; it is who they are as people. They are driven and always will be.

Second, find people with something to prove to the world. You do this by asking questions about their role models, relationships, family, and long-term ambitions. People with fire in the belly usually have someone or groups that have importance to them. Find out who they are, why they are important to them, and what they want to prove at the end of the day. When you’re determined that the candidate will be unrelenting to make a parent proud or prove someone wrong, you should be thinking about where he or she will sit in your office.

Third, find people who have overcome obstacles—real obstacles, such as the loss of a parent, a tragedy, or material setbacks. Ask about their life growing up and the material conditions or events within it. What were their life-changing events? If you want people who will go through walls to succeed, hire people who already have gone through walls in their life.

Find someone with any of these qualities, and more often than not you will benefit every day they are in your employ. After all, fire in the belly comes to work every day and brings energy to every task.

This article was written by Don Rainey and published in Bloomberg Businessweek magazine.