At some point in the interview process, many managers seek a second opinion about the candidates they’re considering. They typically ask one or more other people in the company to interview their top choices and offer feedback. Recently someone asked me a very good question: “Is this step necessary or even helpful?”

My response? Only if it’s done right.

What does “right” mean? For starters, you need to select your additional interviewers carefully. Target those who have more hiring experience than you and whose judgment you trust. Those who might pick up on something you missed.

Maybe your own manager or one of your peers has an excellent track record of hiring great people. Asking that person to meet with your candidates and weigh in on what they see can be very valuable.

It’s also a good idea to ask others to interview your candidates to assess their skills in areas where your expertise isn’t strong. For example, let’s say you’re hiring for a job that requires extensive knowledge of a software program that you don’t personally use. You may want to ask someone on the team who’s more familiar with the software to meet with your candidates so they can ask the right questions to determine skill levels.

But those two scenarios are just about the only situations where second opinions add much value to the process.

What doesn’t work?

Having three or four of your employees interview candidates and offer their opinions just so they’ll feel like they’re “part of the process.” This can be a big waste of time, especially if they aren’t all trained in effective interviewing techniques and end up asking the same questions over and over. Yes, I know the argument that it’s nice to let your current team members meet candidates and give you input on how well individuals would fit in with the existing group. But you should know your team and it’s dynamics well enough to make that determination yourself.

Another mistake, no matter whom you ask to interview your candidates, is not briefing the individual up front on what you’re looking for in the person you hire. You should specifically outline the skills, knowledge, experience level, and personality traits you need and share them with the interviewer. How else will he or she know what questions to ask and what’s important to you?

Finally, you definitely want to avoid having anyone interview your candidates whom you can’t count on to leave a favorable impression. The last thing you want to do is have people you’re interviewing spend half an hour with Susan and her perpetually negative attitude or Bill and his abrasive, snarky comments. So choose carefully.

The bottom line is simple: When you’re considering including others in your interview process, ask this question: “How will this person help me make the best possible decision?” If you can determine specific ways the individual will add value, by all means ask for his or her help. But otherwise, rethink your choice.

Do you routinely ask others in your company to interview candidates you’re considering? If so, how do you choose them? If not, why? We’d love to hear about your experiences in the comments section.

Janna Mansker is vice president of client services for Berke, a human resources consulting firm, where she leads the company’s education initiatives and advocates for clients. She can be reached at janna@berkegroup.com.