Time and again, I have been complimented on my ability to "read" people...in fact, I have made a bit of a career out of it. I am not talking about reading non verbal cues, there is enough information out there to guide anyone in that area. Psychology Today has a whole collection of articles on reading people, it is well worth a read and if you get nothing else out of that collection, remember to just laugh at your boss' jokes. No, I am talking about the ability to sense whether a person is going to be a fit for a team, or if someone is going to cause problems down the road. We often get a sense about other people but are unable to quantify that sense, so we ignore it.
In my experience, my friends do not request any quantifiable data...they just accept that I find one of their potential significant others to be a jerk, or in some cases, an absolute perfect fit. I have had friends take me aside after dinner parties to ask me what I have thought of so and so because they are thinking of doing business with that individual. These people do not ask me to explain exactly why I have these rather strong opinions formed about people I have only just met, they accept them. Now, just because they accept them, it does not follow they do anything about it. And that is okay (although more than one ugly breakup could have been avoided if certain people had just listened to me, just saying).
However, in business, my clients expect more than just a feeling. Understandably, they want something a bit more objective than "He rubs me the wrong way", or "She won't be a fit". Recently, I was in an interview with one of my clients who had already determined that the candidate was not a fit...I came to this brilliant deduction by reading the client's body language, he crossed his arms and leaned back in his chair and stated he had no more questions, Psychology Today may be asking me to write some of these body language articles! However, I had one of my feelings...so I kept the interview going. At the time, I did not know why I had this feeling that the candidate was not only a viable candidate but possibly a really awesome choice. Within 10 minutes, the client's arm came uncrossed and he leaned forward. We will be moving ahead with this candidate.
I present this example so that I can dissect the experience because it happens often, sometimes in favour of the person, sometimes not. At the time, I could not have told you why I thought I needed to keep this candidate talking, I just knew that we were missing something. Listening to your gut is important, but gaining further information in order to make a more objective decision is imperative. This is why I might carry on with an interview longer than seems necessary, why I insist on references being done for anybody a client may want to hire, and why I will never hire someone on the spot. Reading people and assessing any number of unquantifiable things is not a unique skill, lots of us are good at it, but not everyone listens to what their instincts are telling them. Bottom line, use your non quantifiable feelings and balance it out with solid interviewing techniques, and hiring processes (which should always include reference checks).