How to answer “Describe a difficult problem you solved”
Reviewed 19 Sept 2026
Behavioural questions (“describe a time when…”) test whether you can tell a short, true story with a clear result. Most answers fail because they spend a minute on the background and ten seconds on what the candidate actually did.
The well-known STAR pattern (situation, task, action, result) works, provided you weight it properly: keep the situation and task short, and give most of the time to your own actions and the result. In English, the verbs that matter are in the first person and past simple: I noticed, I proposed, I built.
The structure: situation, task, action, result
- Situation
Where and when, and why it was difficult. Two sentences at most.
- Task
What you personally were responsible for.
- Action
Two or three things you did, in order. This is half the answer. Say “I”, not “we”, for your own part.
- Result
What changed, with a number if you have one, and one thing you learned or would do differently.
Before and after
“There was this time when we had a lot of problems with deliveries, it was a really complicated situation, the whole team was stressed, and we had many meetings about it, and eventually we managed to fix it together and the customers were happier.”
- “We” all the way through: the panel cannot tell what this candidate did.
- “Complicated” and “many meetings” are not actions.
- “Customers were happier” is a result nobody can picture.
“Last year, about one in ten of our deliveries in the north region arrived late, and two large customers threatened to leave. I was the analyst responsible for that region. I pulled six months of delivery data and found that most late deliveries came from one depot and happened on Mondays. I visited the depot and saw that weekend orders were being loaded by hand on Monday morning. I proposed a Sunday evening loading shift and ran it as a four-week trial. Late deliveries from that depot fell from ten per cent to under three, and both customers renewed. What I took from it is to go and look at the process in person before trusting my assumptions about the data.”
Phrases you can use
- “Last year, in my role as…,”
- “The difficulty was that…”
- “What made it hard was…”
- “I was responsible for…”
- “My part was to…”
- “The first thing I did was…”
- “I noticed that…”
- “So I proposed…”
- “I ran it as a trial for four weeks.”
- “As a result,…”
- “It went from… to…”
- “What I learned is…”
- “If I did it again, I would…”
Common mistakes
Give yourself fifteen seconds for the situation. If the listeners need more, they will ask.
Credit the team once, then describe your own actions with “I”.
If you do not have an exact figure, give an honest approximate one: “roughly half”, “from days to hours”.
Pick one where something was really at stake and the solution was not obvious.
A ten-minute drill
- Choose one real problem. Write one line each for S, T, A and R.
- Record a 90-second answer.
- In the transcript, mark where the action part begins. If it begins after the halfway point, shorten the opening.
- Record again and count how many sentences start with “I” followed by a verb. Aim for at least four.
Questions people ask
Can I use an example from outside work?
Early in your career, yes: a university project, volunteering, or a personal project with a real result. Later on, interviewers expect a work example.
What if the result was not a success?
A partial success that you describe honestly, together with what you learned, is often more convincing than a perfect story. Do not invent numbers. Interviewers ask follow-up questions.
How many stories should I prepare?
Five or six cover most behavioural questions: a problem, a conflict, a mistake, leading something, working under pressure, and learning something new. Each can be adapted to several questions.