By Jonathan Davis, founder of UmpHub, LLC.

I received a reference phone call yesterday. It was from a staffing firm inquiring about someone who worked for a previous company I was involved in. The poor woman on the phone sounded exhausted and defeated even before she asked me the first question. I found myself wondering, “What box on a piece of paper is she trying to simply check off to say she’s completed this task?”

Two weeks ago, I tweeted about how significant we’ve found reference checks to be in our evaluation process for prospective employees. The statement I made was that we typically can glean about 20 percent of what we learn about someone through the reference process. I received a lot of questions about this statistic. I wish I could take credit, but it was actually Geoff Smart  who helped me figure out that references are a lot more than just asking about dates of employment.

Here are some examples of what I ask when I’m making a reference call:

• Why did you hire him?
• What top two or three biggest outcomes was he hired to achieve?
• Did he achieve them?
• How much direction—at the beginning and throughout his tenure—did he need to be successful? 
• What things did you witness that frustrated him?
• How did he mature during his time with you?
• What advice would you have for on-boarding him effectively and getting him productive quickly? Likewise, for the people reporting to him, what advice would you give for maximizing their relationship with him?

In my experience, if you’ve ever asked a previous manager, “What were his weaknesses?” and gotten the answer of, “You know, I can’t think of any…” it’s because you’re not asking correctly. Everyone has weaknesses, and if you’re not validating them in the reference process, you’re going to significantly slow down your on-boarding process.

Here’s a technique I’ve learned over the years: Document the self-admitted weaknesses of a candidate during the interview process, and then re-position the question that you pose to the previous manager so it sounds more like this: “Mr. Manager, John Doe shared with me that his biggest shortfall while working with you was that he struggled to prioritize his time, which resulted in him missing some pretty key deadlines. Would you agree?” By showing the previous manager that you’ve established enough rapport to have acquired this kind of information from the candidate, you’ll find that he is much more willing to talk about that stated shortfall, as well as other weaknesses.

Here’s one last tip I discovered: During an interview with a prospective employee, ask him who his previous managers were. Write down those names and titles, and then, when you’re ready to move to the next step of the evaluation, ask him to make an introduction with one of those former managers on your behalf. I have found that it’s even better if the candidate copies you on the e-mail to that previous manager. Brad Smart (Geoff’s Dad and author of Topgrading) calls this process “Truth Serum.” This is a terrific approach when it comes to hiring!

There are no shortcuts to getting the best information about a candidate, but I’ve learned that if you take some initiative and do a little more digging, you’ll uncover some valuable information that can help in your decision process. When it comes down to it, you can’t be too sure who you’re bringing to the table; it’s best to learn as much as you can about a candidate before investing in him or her.