Each interviewer will have different criteria and methods they feel will best assess a candidate. One style is to confront a candidate very aggressively to see how they candidate will respond. Often, the questions will focus on failures. One of the most difficult to answer is “Why Shouldn't I Hire You?”
This question will stop a lot of job seekers in their tracks. Most people won't expect it. It is a rare question, but does get asked from time to time. It also requires giving a reason why you should be rejected. This is not a topic many people want to cover in an interview. Hiring managers ask this question for three reasons. First, they may want to make the job seeker uncomfortable to see how they react. Second, they may be assessing the candidate's ability to self assess and admit limitations. Third, they may be fishing for a weakness that they haven't spotted.
If you are asked this question, you need to give a good answer. You can't deflect the answer with something like, “You shouldn't hire me if you don't think I'm the best for the job.” An answer like this will not impress a hiring manager. It does avoid discussing your weaknesses, but it is a very weak answer.
A much better approach is to outline your strengths and weaknesses, and relate these to the job. Show why you are a good choice, and provide aspects of the job that are potential weaknesses for you. If the job is a good fit for your background, your strengths will related to the key priorities of the job and your weaknesses will related to minor responsibilities. If done right, outlining your strengths and weaknesses can help sell you to the hiring manager.
Example
Consider an experienced plant manager interviewing for a plant manager position:
“My background is in leading and managing production teams. I started out as a supervisor and worked my way up. Throughout my career, I have done an excellent job of motivating teams, holding employees accountable for their performance and controlling costs. I've picked up a lot of technical knowledge along the way, but I am not expert on the equipment. I have succeeded by using the technical expertise within my team. If your organization needs a hands on plant manager that can troubleshoot processes, I'm probably not the best candidate for the job. I will perform much better in a role where technical expertise exists in the organization and needs skilled leadership to maximize its effectiveness.”
This answer focuses on the candidate's strengths and gives a reason why the candidate should be hired. It also provides a reason not to hire the candidate. Most plant management jobs will seek a strong leader and not a pure technical expert. This makes the answer safe in most situations. There are exceptions. Some plants are technically very weak. They need a top leader that can provide engineering, process and equipment expertise. If this is the case, the answer will hurt the candidate's chances. This may not be a bad thing, though. If the candidate really isn't a technical expert, a role requiring this background will not be a fit.
Preparing an Answer
Should you prepared an answer for this question? The question is rare, and may not come up in any of your interviews. Despite this, I recommend preparing an answer. The reason is simple. If you can articulate very clearly why you are both a strong and weak fit for a position, you can sell your potential in almost any interview answer.