Why interviewers ask this question
This question tests genuinely proactive thinking: whether you notice early warning signs and act before a problem becomes serious, rather than only ever reacting after something has already gone wrong. Employers value this highly because preventing a problem is almost always cheaper and less disruptive than fixing one after it has escalated.
How to structure your answer using STAR
Choose a real example where you noticed a genuine early warning sign that others had not yet flagged, and acted on it before it became a bigger issue. Briefly explain the situation and what you noticed, then focus the action on what you specifically did: raising it clearly, proposing a fix or mitigation, and following through, even if it was not formally your responsibility to do so. Close with a clear result showing the problem was avoided or significantly reduced.
A strong example answer
"While reviewing a routine report, I noticed a small but steadily growing discrepancy in reconciliation figures that others had not flagged, since each individual instance looked minor. I traced it back to a specific process change made a few weeks earlier and raised it immediately with the finance lead, before it grew into a much larger, harder-to-trace discrepancy. We corrected the process within days, and the finance lead specifically noted that catching it early likely saved a significant reconciliation headache at year end."
Mistakes to avoid
Avoid a story where you reacted to a problem that had already clearly happened, since this question specifically wants evidence of early, proactive detection. Avoid vague claims of being "detail-oriented" without a specific, concrete example of catching a genuine early warning sign that others missed.