It’s every business owner’s worst nightmare: You hire someone who looks smart on paper and seems fine in the interview, who then turns out to be a disaster. And not just a run-of-the-mill disaster. As recent incidents in Aurora, Colorado, and New York City have shown, it’s possible for heinous acts to be committed by people who, outwardly at least, appear perfectly well adjusted.

Mental illness is a taboo subject on so many levels, and that taboo puts small businesses at risk when they hire. I have worked with some absolutely brilliant people who live with mental health challenges. When managed properly, these illnesses can be kept in check, and the wonderful person underneath can shine. I wish our society were more open, because it sure would help if employers and employees could openly talk about these issues. 

It used to be that employers would look for gaps on a resumé and flag those as risks. Why? Because people suffering from certain mental illnesses often had gaps in their employment history. That’s not a good approach, but there isn’t a good approach, really. In today’s economy, so many people have gaps because their companies went out of business or downsized that even this lame approach is no longer the crutch it once was. Not to mention the ethical issues surrounding this type of discrimination.

One of an entrepreneur's best friends, then, is the reference check. But for reasons both personal and legal, it can be hard to get good information out of even the most cooperative reference.

I am not an attorney, and there is no legal advice in this column. But I have learned a few things over the years that make me more prudent in hiring or allying with others in business situations.

No one wants to give a bad reference. For one thing, people do not want to be sued! You may think that calling every reference on a list means you’ve been diligent, but are you digging enough to get past the surface veneer? Open-ended questions, such as these, can uncover a variety of troublesome behaviors, not matter what their cause:

  • Tell me about a time when the candidate had a conflict with a co-worker. How did the situation unfold?
  • What kind of schedule did the candidate keep? Did co-workers ever have trouble working with him or her because of schedule issues? Tell me about a time when this was a problem.
  • Tell me about a time when the candidate surprised you. What were the circumstances? What did he/she do?
  • If you were to hire the candidate again, what role do you think would be ideal? What role would not be a good fit, and why?
  • We all get frustrated with each other from time to time. Tell me about a time you were really frustrated with the candidate.
  • In which situations does the candidate really shine? Tell me about an example.

I have also learned to listen for euphemisms. If former colleagues describe someone as “erratic,” that could indicate a more serious problem.

Find third-party references. Can you talk to someone who hasn’t been prepped to be a reference for your candidate? If you can, you are more likely to get a spontaneous answer to your questions rather than a polished, prepared one. Some companies have policies against giving references beyond confirming dates of employment, so finding someone who has moved on to another job since working with your candidate can often be a better source of information. Find out how your candidate interacted with colleagues. Was he or she a team player, prima donna, or lone wolf?

Why did your candidate leave each position listed on the resumé? This is a key question, especially for someone with a lot of job changes. In the “old days,” a series of job changes was a red flag for a serious problem. If someone hopped from job to job, you wondered if he or she had trouble getting along with others. Now, you could just be interviewing a hot software engineer who legitimately jumps at new opportunities every year (or less!).

Don’t just take the first answer--dig into this. Look for stories that hang together and stories that don’t. Inconsistencies are a red flag. See if you can corroborate the stories through reference checks, too.