What is a competency interview, and what is the STAR method?
A competency — or behavioural — interview asks about things you have actually done, on the premise that past behaviour predicts future behaviour better than hypothetical answers do. STAR is the structure that makes answering one coherent.
How to recognise it. The questions begin "Tell me about a time when…" or "Give me an example of…" rather than "How would you…". That distinction matters: a hypothetical question invites what you think should happen; a competency question asks for evidence.
Why employers use it. Unstructured interviews are poor predictors of performance, and are highly susceptible to rapport and similarity bias. Structured interviews, scored against defined criteria, predict considerably better — which is why public sector and large organisations use them almost exclusively.
STAR:
Situation — brief context. One or two sentences.
Task — what you specifically needed to achieve, and why it was difficult.
Action — what you did, in detail. This should be the bulk of the answer.
Result — what happened, quantified where possible, and what you would do differently.
Where candidates actually lose marks:
Spending too long on situation. Interviewers are scoring the action; the context is scaffolding.
Saying "we". Scorers cannot credit you for what the team did. Use "I" for your own contribution, even where it feels immodest — this is the most common and most costly error.
Choosing an example that does not evidence the competency asked about. Read the criterion: "influencing" and "teamwork" need different stories.
Omitting the result, which is frequently where the marks concentrate.
Being hypothetical, answering what you would do.
How to prepare efficiently:
Work from the person specification. The competencies being assessed are usually published, and the questions map directly onto them.
Prepare six to eight versatile examples rather than one per question — a good example can evidence several competencies with a different emphasis.
Include a failure, since resilience and learning are commonly assessed and a polished-only history reads as evasive.
Rehearse aloud, since the structure is harder to hold under pressure than it looks.