Determining what someone you don't know well will really be like once you know them better? That's tough.
Some, like, Thomas Edison, tried to be clever. Edison offered candidates for research assistant positions a bowl of soup to see if they would add salt or pepper to it before they tasted it. Those who did were automatically ruled out. Assumptions are like Kryptonite to innovation, and Edison didn't want to hire people whose personalities led them to make assumptions.*
Fortunately, you don't need to go to those lengths to get a sense of a potential employee's personality. (Or partner, or customer, or vendor, or supplier...)
To find out what someone is really like, a 2010 study published in Journal of Personality and Social Psychology says just ask them to rate a positive (or negative) characteristic of three people.
For example, you might say, "Think of three people you know well. How would you rate them in terms of cooperation, collaboration, and teamwork?"
The researchers found an individual's tendency to describe others in positive terms is an important indicator of the positivity of that individual's own personality traits. Judge others as enthusiastic, happy, kind-hearted, courteous, emotionally stable, and capable and you're likely to be the same way.
Rate people you know as good team players and you're likely to be a good team player, too.
"Seeing others positively reveals our own positive traits," the researchers write.
The same goes for the flip side. "A huge suite of negative personality traits are associated with viewing others negatively," they write. "The simple tendency to see people negatively indicates a greater likelihood of depression and various personality disorders." (Yikes.)
The study suggests that asking someone to rate the personality of real people (without asking for names, of course) may help you learn as much about the person providing the personality description as the person they describe.
People who see others as generous tend to be generous. People who see others as polite and friendly tend to be polite and friendly. People who see others as good leaders tend to be good leaders.
Try it. Ask Instead of asking someone to describe one of their own personality traits -- which is at best awkward and uncomfortable, and at worst creepy and invasive -- ask them to describe a few people they know.
How they rate other people -- both positively and negatively -- may say just as much about them.
Especially if they rate people positively.
*Even though Edison used the test to, yep, make an assumption.