Take Thomas Edison. When he interviewed candidates for research assistant positions, he offered them a bowl of soup. Why? He wanted to see whether they would add salt or pepper to the soup before they tasted it.

Those who did were automatically ruled out. Edison wanted people who didn't make assumptions, since assumptions tend to be innovation killers.

Many people use little tests as part of their evaluation process. For years I used what I called the "receptionist test." Interviewees give you their best: They're up, engaged, and switched on. But how do they act when they aren't trying to impress you? What candidates do while they're waiting in your lobby can tell you a lot.

So I would always ask the receptionist how she was treated. I found out what they did while they waited in the lobby. I asked if there were any chance encounters with other employees. Occasionally I picked up a disconnect between the show a candidate put on for you and the way they acted around with people they weren't trying to impress.

After all, a nice guy in the lobby may not be a nice guy on the job, but a jerk in the lobby will always be a jerk on the job.

Or you could use your own version of the Chad Knaus "car test" (my quotation marks.)

Chad is a six-time NASCAR Sprint Cup champion crew chief for the #48 Chevrolet driven by Jimmie Johnson. (The team is owned by Hendrick Motorsports; if you aren't familiar with NASCAR, a crew chief at HMS is to auto racing as the head coach of the Patriots is to football.)

Every candidate takes an emotional intelligence test before the interview. "There is no good or bad result," Chad told me. "Whether an individual is introverted or extroverted, for example, doesn't affect their ability to do the job. Great teams are made up of all sorts of individuals. What the EI test does do is give me a sense of how to conduct the interview so I can better relate to that person."

After the interview, Chad will sometimes walk with candidates to the parking lot to say good-bye... and to check out their cars.

"I don't care what kind of car they drive," Chad said. "Old, new, expensive, inexpensive... none of that matters at all. But I do care about whether they take care of their car. If food wrappers are lying on the seats... if the car isn't clean and well maintained... I figure if you don't take good care of your stuff, you aren't going to take good care of ours."

Is Chad's car test the only hiring criterion that matters? Of course not -- but it is another tool to evaluate whether a candidate is a good fit for the team and the overall culture of the Hendrick organization.

Think about what matters most in your organization and devise your own way to test for cultural fit. Maybe you'll use a version of the server test. Maybe you'll do what a friend does and see if the candidate pitches in with you to help stack a few boxes at the end of an assembly line. (Hopefully you won't go so far as Bill Gates once did and memorize license plates in the company parking lot so he could tell who was still at work and who was not.)

Whatever you do, the goal is to learn more about the candidate so you can make a better hiring decision. Think of it as another way for potential hires to show they are a great fit for the position, and your business.

While it's only one data point in a larger set of hiring criteria, that's okay.