What are your main strengths and weaknesses?

• How well you know yourself. Consultants get very direct feedback after every project, and someone who can already name their weak points will improve faster than someone who is discovering them.
• The sincerity of the weakness. Perfectionism and working too hard have been heard a thousand times. A real weakness, plainly stated, builds trust.
• What you do to improve. A weakness with no plan is a problem. A weakness with a method for correcting it and early results is evidence of maturity.
• The relevance of the strengths. They should be useful on a project: analytical rigour, the ability to simplify, reliability, ease with varied people.

1. 1

   Lean on feedback you received

   The most credible strengths and weaknesses are those other people pointed out: an internship review, a comment from a teammate. Name the source, since it is worth far more than a self-assessment.
2. 2

   Prove each strength with a fact

   One sentence to name the strength, two or three to tell the moment it made a difference. Two well illustrated strengths are enough.
3. 3

   Pick a weakness that is real but not disqualifying

   Avoid anything at the heart of the job, such as numbers or teamwork. Honest examples: difficulty delegating, speaking up in front of experienced people, asking for help early enough, stopping when the work is good enough.
4. 4

   Show the work in progress

   What you have put in place to correct the weakness, and a sign that it is starting to work. Do not claim to have eliminated it.

"My first strength is making complicated things simple. My supervisor told me so at the end of my last internship: he gave me the notes meant for senior management because he had almost nothing to rewrite. The second is that I keep my commitments. When I say Thursday it is Thursday, and if I can see I will not make it, I say so on Tuesday.

On the weakness side, the main one is that I ask for help too late. I prefer to work things out alone, and I have lost a day on a point a colleague would have unblocked in ten minutes. It was pointed out to me during an internship. Since then I set myself a time limit: if I have made no progress after an hour, I go and ask..."

This example is made up: it shows the tone and the construction, not a script to memorise. Your answer has to come from your own experience or from the data the interviewer gives you.

• The weakness dressed up as a quality: "I am too much of a perfectionist", "I care too much". The interviewer asks again for a real one, and you have lost time and some credit.
• A list of adjectives with no proof: rigorous, curious, dynamic. Without a story those words are worth nothing.
• A disqualifying weakness, such as "I do not like numbers", or the opposite, a trivial one unrelated to work.
• Saying the weakness is solved. If it is, it is no longer a weakness and you have not answered.