There are three domains of knowledge:
  1. 1. What you know
  2. 2. What you know you don’t know
  3. 3. What you don’t know you don’t know

The first two domains are easily handled. In terms of a job, there are things you know about the job. There are things you know you don’t know such as exact responsibilities, compensation, who you will report to, etc. To learn this information you know what questions to ask. The third domain is the tricky one. How do you find out information you don’t even know exists, where do you begin?
It is what you don’t know you don’t know that typically causes you the greatest difficulty; “If I knew that before I took the job…….” To uncover this domain of knowledge, ask questions that do not bias or lead the interviewer. Here are some examples:
You want to find out how many hours people work on the job. Many applicants will ask “How many hours do people typically work”. The interviewer replies: ”Typically 35 to 40 hours per week”. Sounds OK, then comes holiday time and you are putting in 50 to 60 hours and are overworked and miserable. An open question would have been more revealing, for example “Tell me about work hours on the job”. This question opens the opportunity for the interviewer to say “We typically work 35 to 40 hours per week except for holiday time when we work 50 to 60 hours and everyone feels overworked.”
Another example – You want to find out what it is like to work at the company. You can ask the question, “What do you like and dislike about working here” The answer will be focused on the interviewer’s predominant likes and dislikes. A better question is “So, tell me about working here”. This question opens up the possibility of hearing about challenges, relationships, concerns, excitement, etc, etc. You may very well hear about something you would not have thought to ask about.
The more exact and detailed your question the less likely you are to hear what you don’t know you don’t know. With open, non-leading, and non-biasing questions, the interviewer has the opening to respond from their own perspective. Once you hear their answer there may be a whole area of information you want to learn more about, and now you know to ask.