Knowledge can be put into three classes:

1. What you know
2. What you know you don’t know
3. What you don’t know you don’t know

The first two classes are easily managed. The things you know, you are aware of. The things you “know you don’t know” you can ask questions about. The third class is the most challenging; how do you learn about things you are not even aware of and cannot formulate a question about? In the selection process, the third class of knowledge contains very rich information. Information that may make the difference between a high potential hire and a bad hire.

A well organized and comprehensive selection and interviewing process is good at covering the first two classes of information. The “what you know” comes from reading the candidate’s resume and careful screening. When the candidate gets to the interview, the focus becomes “what you know you don’t know,” and the desired information is obtained through a list of questions. The third class of knowledge “what you don’t know you don’t know” is difficult to obtain. Unfortunately, this class of knowledge often comes when the candidate has been on the job for six months and it often sounds like this, “If we had known then what we know now we never would have hired him.”

Asking good questions
The interesting paradox is that “what you don’t know you don’t know” cannot be discovered through questioning. Each question you ask closes down the possibility of the candidate revealing new and unconsidered information. So how do you obtain information without asking a question? By making a request and then asking questions about what you hear.

For example, a typical question about the candidate’s future career plans would be: “Where do you see yourself in five years?” With a well prepared candidate, this question elicits a practiced response including increasing responsibility, moving up through the organization, contributing to the bottom line, etc., etc.

Contrast posing a question with making the request: “Tell me about work.” A request is usually responded to with a question such as, “What about work? What I am like at the office? The work I would love to do? What annoys me most about the people I work with?” Now you have four pieces of information upon which you can follow up. A follow-up question would include the candidate’s language, “Tell me about the work you would love to do.” or “Tell me about what annoys you most about the people you work with.” Did you know the candidate has work they would love to do, or that they have a set of annoyances with the people at work? Probably not. Now you are into the realm of ‘what you don’t know you don’t know.”

Making non-direct requests to elicit internal thinking
The skill here is making a non-directive request that elicits the candidate’s internal thinking and then following up on that thinking. If you are trying to learn about a candidate’s trustworthiness or ethics, you could ask a question such as, “Do you think it is OK to hold back important information from a client that may annoy or concern them? Or you could make a request such as “Tell me about honesty.” The request will elicit a response that comes from the candidate’s internal, and unknown, frame of reference instead of your directed question.

As the old saying goes, “It’s what you don’t know that will kill you.” To know it all, all three classes of information must be explored. It is easiest to ask a set of predetermined questions to learn about what “you know you don’t know.” However, making requests and learning about those things completely missing may provide you with the key information you need to make a best-fit hiring decision.