Interview Question of All Time

Over the course of the past 20 years, I've been searching for — among other things — the single best question to ask in an interview. What I wanted to create was a One-Question Interview, a stand-alone query that would pierce through the veneer of generalizations, overcome typical candidate nervousness, minimize the impact of the candidate's personality on the interviewer, eliminate the exaggeration which many candidates adopt as an interviewing ploy and actually determine if the candidate is competent and motivated to do the work required. I also wanted this question to begin the recruiting process, convincing the candidate by the question itself that the person asking it was sophisticated and professional, and that the company involved was a great place to grow a career.
As a goal, this, as I'm sure you'll agree, is not chopped liver. And through years of trial and error, I finally hit upon one question that did it all.

If you were allowed to ask only one question during the course of the interview, this would be it:

Please think about your most significant accomplishment. Now, could you tell me all about it?

To see why this simple question is so powerful, try it out on yourself. Imagine you're the candidate and I've just asked you this question. What accomplishment would you select? Then imagine over the course of the next 5-20 minutes that I obtained the following information from you about this accomplishment:

A complete description of the accomplishment
The company you worked for and what it did
The actual results achieved: numbers, facts, changes made, details, amounts
When it took place
How long it took
The importance of this accomplishment to the company
Your title and role
Why you were chosen
The 3-4 biggest challenges you faced and how you dealt with them
A few examples of leadership and initiative
Some of the major decisions made
The environment and resources available
How you made more resources available
The technical skills needed to accomplish the objective
The technical skills learned and how long it took to learn them
The actual role you played
The team involved and all of the reporting relationships
Some of the biggest mistakes you made
How you changed and grew as a person
What you would do differently if you could do it again
Aspects of the project you truly enjoyed
Aspects you didn't especially care about
The budget available and your role in preparing it and managing it
How you did on the project vs. the plan
How you developed the plan
How you motivated and influenced others, with specific examples to prove your claims
How you dealt with conflict with specific examples
Anything else you felt was important to the success of the project
If the accomplishment was big enough, and if the answer was detailed enough to take 15-20 minutes to complete, consider how much I, or any interviewer, would know about you. The insight gained from this type of question would be remarkable. Just about everything you need to know about a person's competency can be extracted from this type of question.
Most people would agree this type of question is very revealing. But the real issue is not the question: it's the information that's given in response that's most important. Few people are able to give this type of information without additional prompting from the interviewer. This is what real interviewing is about — getting the answer to this very simple but very powerful question. Don't spend time learning a lot of clever questions to ask during the interview: spend time learning to get the answer to just this one question. The key: understand the accomplishment, the process used to achieve the accomplishment, the environment in which the accomplishment took place and the candidate's role.

To expand upon the assessment, you can ask this same question in the same level of detail for a variety of different accomplishments. Ask the candidate to describe two to three different individual and team accomplishments for the past five to ten years. Put them in time order to see the growth and impact over time in different jobs, and with different companies. Also ask about accomplishments that directly relate to job specific needs, for example, "Describe your biggest accomplishment in setting up manufacturing scheduling systems."

With this approach to digging in and finding out about major accomplishments you'll have all you need to make a reasoned evaluation of a person's ability to deliver similar results in a similar environment to your own. Here's just a little of what you'll learn about a candidate from this type of questioning — initiative, commitment, team leadership, growth, potential, compatibility, comparability, character, true personality, applicable experience, ability to learn, and true interest and motivation to do the work required.

Few candidates will give you all of this information on their own, so it's the digging in that matters. It's the interviewer's responsibility to get this valuable information from the candidate, not the candidate's responsibility to give it to the interviewer. By fact-finding this way, you put all candidates on a level playing field. And when you can get all members of the interviewing team to conduct their interviews this way, you'll remove another key source of hiring errors — the tendency of most interviewers to talk too much, listen too little and ask a bunch of irrelevant questions. One question is all it takes.