Competency-based interview questions to ask candidates

Ask a candidate whether they work well under pressure and every single one will say yes. Ask them to describe the last time a project was falling behind and what they actually did about it, and the answers separate immediately. That gap between claims and evidence is exactly what competency-based interview questions are designed to close.

At Digital Waffle, we help employers across tech, digital, data and marketing structure their interviews every week, and competency-based questions come up in almost every briefing. The employers who use them well consistently make stronger hires, because they walk out of interviews holding evidence rather than impressions.

In this blog, we explain what competency-based interview questions are, why they work, which competencies to assess, the specific questions to ask for each one and how to run and score a competency-based interview properly.

What are competency-based interview questions?

Competency-based interview questions ask candidates to describe specific situations from their past where they demonstrated a particular skill or behaviour, such as problem solving, teamwork or leadership. They usually start with phrases like "tell me about a time when" or "give me an example of", and they work on a simple principle: past behaviour is one of the strongest predictors of future performance.

They differ from hypothetical questions, which ask what a candidate would do in an imagined situation. Hypotheticals test imagination and interview technique. Competency questions test what the person has actually done, which is the evidence a hiring decision should rest on.

Why should employers use competency-based interviews?

Competency-based interviewing takes slightly more preparation than an unstructured conversation. The return on that preparation shows up in the quality and consistency of your hires.

They give you evidence instead of opinions

Unstructured interviews reward candidates who talk well about themselves, which is a different skill from doing the job. Competency questions force every claim to be backed by a real example, with a situation, actions and an outcome you can probe.

In our experience, this is where interviews most often change direction. Candidates who sounded strong in general conversation sometimes cannot produce a single concrete example, while quieter candidates turn out to have the deepest evidence. Without competency questions, you would have hired the wrong one.

They make hiring fairer and more consistent

When every candidate answers the same competency questions, you can compare answers directly rather than comparing how each conversation happened to feel. That consistency reduces the influence of bias, first impressions and interviewer mood on the final decision.

It also protects your process. Structured, consistent questioning is far easier to defend and explain, to internal stakeholders and to candidates, than decisions based on chemistry.

They predict performance better than a CV can

A CV tells you what roles someone has held. Competency answers tell you how the person operates inside those roles, which is what actually determines whether they succeed in yours. Two candidates with identical CVs can give completely different competency answers, and the difference is usually the hire.

Read more: How to screen candidates for long-term success

Which competencies should you assess?

The right competencies come from the role, not from a generic list. Before the interview, pick the four to six behaviours that most decide success in this specific job, using the job description and the experience of people already doing similar work.

A marketing manager might need communication, stakeholder management and adaptability. A data engineer might need problem solving, attention to detail and collaboration. Assessing more than six competencies in one interview usually means assessing none of them properly.

Competency-based interview questions to ask candidates

These are the competencies employers ask us about most, with questions that work for each and what a strong answer sounds like.

Communication

Ask: "Tell me about a time you had to explain something complex to someone without your technical background. How did you approach it?" or "Give me an example of a time your communication prevented a problem, or fixed one."

Strong answers show the candidate adjusting their style to the audience and checking understanding, not just transmitting information. Listen for who they were speaking to, what they changed and what happened as a result.

Teamwork and collaboration

Ask: "Tell me about a time you worked with a colleague whose approach was very different from yours" or "Describe a project where the team was struggling. What part did you play in turning it around?"

Strong answers balance "I" and "we". You want to hear the candidate's specific contribution, and you also want to hear genuine credit given to others. Candidates who describe every team success as their own tend to repeat that pattern once hired.

Problem solving and decision making

Ask: "Walk me through a difficult problem you solved recently. How did you work out what was actually wrong?" or "Tell me about a decision you made with incomplete information. How did you decide, and what happened?"

Strong answers reveal a process: how the candidate broke the problem down, what options they weighed and why they chose the path they did. The quality of the thinking matters more than whether the outcome was perfect, and candidates who own imperfect outcomes honestly are usually the stronger hires.

Adaptability

Ask: "Tell me about a time when priorities changed suddenly on something you were working on" or "Give me an example of learning a new skill or tool because a role demanded it. How did you go about it?"

Strong answers show the candidate responding to change with action rather than frustration. This competency matters more each year in tech, digital, data and marketing roles, where the tools and priorities genuinely do shift under people's feet.

Read more: The importance of hiring for adaptability

Leadership and influence

Ask: "Tell me about a time you had to bring people with you on a decision they initially disagreed with" or "Describe a situation where you led something without formal authority."

Strong answers show influence through credibility and communication rather than position. This pair of questions works for leadership hires and for individual contributors alike, because influence without authority is one of the most reliable signals of future leadership.

Ownership and accountability

Ask: "Tell me about a mistake you made at work. How did you handle it?" or "Give me an example of something you delivered end to end. What did owning it actually involve?"

Strong answers name the mistake plainly, describe the fix and show what changed afterwards. Candidates who cannot produce a single mistake, or whose mistakes are always someone else's, are showing you how they will handle problems on your team.

How to run a competency-based interview

Good questions only deliver if the interview around them is structured properly. These are the steps that make the difference.

Choose the competencies and questions before the interview

Agree the competencies, the questions and who asks what before any candidate walks in. Every candidate for the role should face the same core questions, because that is what makes their answers comparable.

This preparation takes half an hour per role and pays for itself many times over across a shortlist.

Use the STAR method to structure answers

STAR stands for Situation, Task, Action, Result. It is a simple structure for competency answers: the context, what needed doing, what the candidate specifically did and what happened. Many candidates know it, but the framework is more useful to you as the interviewer.

When an answer is missing a component, ask for it. "What was the result in the end?" or "What did you specifically do, rather than the team?" are the follow-ups that turn a vague answer into usable evidence.

Score answers against a simple framework

Decide before the interview what a strong, acceptable and weak answer looks like for each competency, and score every candidate against that scale straight after the conversation. Scoring immediately matters, because detail fades within hours.

Scorecards also make the debrief between interviewers faster and more honest, since everyone is comparing the same evidence rather than trading general impressions.

Read more: How to assess soft skills in interviews

Leave room for the conversation to breathe

A competency interview should not feel like an interrogation. Introduce the format at the start, give candidates time to think before they answer, and let good answers develop before moving to the next question.

Candidates perform closest to their true level when they are comfortable, and your evidence is only as good as the performance you made possible.

Common mistakes to avoid with competency-based interviews

The method is reliable, but a few habits quietly undermine it. These are the ones we see most.

Accepting general answers instead of examples

The most common failure is letting "I always make sure to communicate clearly with stakeholders" pass as an answer. That is a claim, not an example, and it contains no evidence at all.

Hold the line politely. "Can you give me a specific time that happened?" is the single most useful sentence in a competency interview, and you may need it several times per conversation.

Treating hypothetical answers as evidence

"What would you do if" questions have a place, especially for candidates moving into a first-time role where past examples are limited. Just be clear with yourself about what they prove. A polished hypothetical answer demonstrates thinking, not track record.

Where a candidate has relevant history, always prefer the real example. Where they do not, give the hypothetical answer less weight in your final decision.

Forgetting to sell the role

An interview that is all assessment leaves strong candidates cold, and strong candidates are the ones with other options. Build in time to talk about the role, the team and the direction of the business, and to answer the candidate's own questions properly.

Read more: How to interview candidates: A complete guide for hiring managers

Running it all without support

Designing competencies, writing questions and calibrating scorecards takes time that stretched hiring teams do not always have. A specialist recruitment partner can carry much of it, and pre-screen for the competencies before candidates ever reach your interviews.

At Digital Waffle, we screen candidates against the competencies that matter for each role we work on across tech, digital, data and marketing, and we share what we observe with hiring teams before the first interview. That head start means your interview time goes on the candidates whose evidence already stacks up.

Competency-based interview questions work because they replace the question every interviewer is really guessing at, "will this person perform?", with something answerable: "show me when you already have." The evidence is nearly always there. The questions are just how you surface it.

The employers who hire most reliably are not the ones with the toughest interviews. They are the ones who decided what evidence the role required, asked every candidate for it and believed the examples over the impressions.

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