I've interviewed a fair number of folks in my years. Not just for jobs, but possible vendors as well. We also do interviews as part of our branding process.
I'm in the middle of reading The Unpersuadables, which talks a lot about how our brains are set up to lie to us, even when we are trying to be truthful. This makes interviews problematic. People generally want to present a positive view of themselves and the world, so they are unlikely to admit the negative side of things.
A recent University of Utah study suggests a tricky phrasing to elicit an honest response:
For example, instead of asking, “Do you ever use work time for personal email or social media?” or “Have you used a sick day when you weren’t actually sick?” VanEpps suggests phrasing your question with the negative assumption. “‘You’ve used a sick day when you weren’t sick, right? Or ‘You use work time for personal email, right?’ ”
They did find this only works with common behaviors. Asking something like, "You do steal other employee's lunches, right?" would be a bridge too far.
This makes some sense, by normalizing the potentially negative behavior you have created space for conversation.
In brand interviews we often ask about negative interactions. Rather than asking, "Can you think of a time where your interactions with Brand X weren't ideal?" this research would suggest we should ask, "We've heard about some not ideal interactions with Brand X, can you tell me one you have had?"
We are social animals. By making the interviewee's negative actions part of the group, it allows them to be honest.
And the honest truth is we all do some personal emailing at work, have taken sick days because we just wanted a day off, and have had at least one less than ideal interaction with a brand.
In all of those cases an honest answer is always better than a flat denial.