The interview is so much more than just selling yourself. Yes, you have to do that, but you are there really to see if the job is a good fit for you. That requires you ask some really good questions. Many of those questions are rooted in what is important to you in your next job. Oh FYI, that means, you have to know what you want. (That will come in tomorrow's post).
Asking "Why is this position available" can be incredibly insightful. You want to understand the logic the company has for needing this position. Is it turnover, internal advancement, growth?
If the interviewer tells you: You are the 5th person we've hired in the last year… this begs a follow-up question or two. Were the others fired, promoted, did they quit and why? If they were fired, it could be a management problem and you need to explore the management style and meet that manager. It could be that the goals of the position were set too high. Explore the expectations of the position fully. If they have been promoting these people, find out why. Growth, new projects, both. Others leaving? If there has been a mass exodus higher up in the company, that's good to know, find out why.
What if they tell you the position is brand new. Again, find out why. What is driving the addition of this job. Keep in the back of your mind the old saying: "last in, first out". You also want to find out how performance will be evaluated for this new position and how they came up with the numbers. But what if they tell you that they haven't defined the performance expectations yet, they're waiting for the person to start…warning, danger Will Robinson. An undefined job is usually first on the chopping block. A brand new position boasts of risk and reward. That can be a wonderful challenge to some people. At least enter into the job knowing what you are faced with.
It is not only ok to ask this question, it is manditory. It would also be a good idea to ask the different people you interview this question to see if their answers match.