20 Interview Questions That Actually Predict Job Performance

The interview questions you ask candidates might feel thorough, but research shows traditional unstructured interviews barely perform better than random selection. A U.S. Department of Labor study found that poor hiring decisions cost companies at least 30% of the employee’s first-year salary-and for specialist roles in tech or e-commerce, that figure escalates to between 50% and 200%. The difference between an effective interview and a costly mishire often comes down to asking the right questions in the right way.

• Why structured interview questions predict performance more than twice as accurately as casual conversations
• The behavioural consistency principle that separates effective questions from time-wasters
• Specific questions that reveal resilience, strategic thinking, and cultural contribution
• How companies like Amazon and Stripe structure their interview process
• Practical scoring systems that eliminate subjective bias from your decisions

These evidence-based techniques have helped tech, e-commerce, and creative agencies—from our Recruitment Agency in San Francisco to our Recruitment Agency in San Jose—significantly reduce hiring costs and improve candidate quality for specialist roles.

Your gut feeling about candidates is probably wrong.

Structured interviews have a validity coefficient of 0.43-0.51, whilst unstructured interviews score only 0.24. What does that mean in practical terms? By structuring the process, you can more than double your accuracy in predicting job performance.

The “gut feeling” trap catches even experienced hiring managers. You have a pleasant conversation with someone, they seem smart and personable, and you convince yourself they’ll be excellent. But correlation isn’t causation. Likeability doesn’t predict performance.

Google learned this lesson the expensive way. Their internal data proved that brain teasers (“How many golf balls fit in a Boeing 747?”) were completely worthless for predicting performance. Despite feeling clever and discriminating, these questions measured nothing except a candidate’s tolerance for arbitrary puzzles.

The result?

A complete overhaul of their interview methodology, focusing on evidence-based approaches rather than the interviewer’s confidence in their own judgement.

The Behavioural Consistency Principle provides the foundation for effective questioning: the best predictor of future behaviour is analysing past behaviour in similar situations.

This means your questions should focus on “Tell me about a time when…” rather than “What would you do if…” Hypothetical scenarios allow candidates to craft ideal responses without proving they’ve actually demonstrated that behaviour under pressure.

But there’s a catch:

You can’t just ask behavioural questions randomly. Before writing questions, conduct a proper job analysis to identify the specific competencies the role requires. A developer needs different competencies than a creative director, and your questions should reflect those distinctions.

At 80Twenty, we start every recruitment project by defining the 4-6 core competencies that genuinely differentiate high performers in that specific role. Generic questions produce generic hires.

Tech, e-commerce, and creative roles all share one requirement: the ability to navigate uncertainty without falling apart.

Here are the questions that reveal whether someone possesses that resilience:

What you’re listening for: ownership, not blame-shifting. Candidates who claim they’ve never experienced failure lack either experience or self-awareness. Strong answers acknowledge what went wrong, explain their specific response, and detail what they learned.

Weak answers identify external factors (the client changed their mind, the budget was cut, the timeline was unrealistic) without explaining how the candidate adapted their approach.

This measures coachability and emotional intelligence. The ability to receive criticism without defensiveness is essential for growth-particularly in fast-moving environments where feedback loops determine success.

Listen for specific examples of implementation, not just acceptance. “I thanked them for the feedback” is insufficient. “I thanked them for the feedback, then spent the following week shadowing a colleague who excelled in that area” demonstrates genuine responsiveness.

This tests collaboration and empathy. Can the candidate adapt their communication style, or do they see differences as obstacles? In specialist roles where cross-functional collaboration determines results, this competency separates productive team members from sources of friction.

Task executors follow instructions. Strategic contributors identify better approaches.

For marketing, creative, and senior specialist positions, you need people who don’t wait for permission to think.

Strong answers balance learning with delivering early value. They should mention stakeholder conversations, understanding existing processes, and identifying quick wins-not just diving into execution without context.

This question also shows whether the candidate has researched your company. Responses that could apply to any organisation suggest superficial preparation.

This measures proactivity. Strong candidates don’t wait for instructions-they act on their own initiative to improve operations. In agencies and e-commerce businesses where margins depend on efficiency, this mindset directly impacts profitability.

Think of it this way:

You’re not just hiring hands to execute tasks. You’re hiring brains to identify what tasks matter most.

Lou Adler developed a methodology that replaces multiple surface-level questions with comprehensive exploration of a single achievement.

The core question: “Describe your most significant career achievement to date.”

Then spend 15-20 minutes on follow-up questions: “What were the actual results?”, “What was your specific role versus the team’s?”, “What obstacles did you encounter?”, “How did you grow as a person?”

It’s difficult to bluff through 20 minutes of detailed scrutiny. This approach reveals true competence level, motivations, and problem-solving methodology in ways that prepared responses to standard questions cannot capture.

The candidate’s comfort level during this extended exploration tells you something important: people who’ve genuinely accomplished difficult things enjoy discussing the details. Those who’ve exaggerated their résumé grow increasingly uncomfortable as your questions become more specific.

The phrase “culture fit” often masks a preference for hiring people identical to existing team members. That’s how you build homogeneous teams that lack the diverse perspectives needed for innovation.

Shift your focus to “culture add”-what new perspective will this person bring?

This reveals curiosity and a growth mindset. The specific content matters less than the enthusiasm they bring to the discussion. People who stop learning become obsolete in industries that evolve rapidly.

You’re assessing whether the candidate will thrive, but also whether they can contribute new perspectives to the team’s current dynamics. Sometimes the best hire challenges your existing approach.

This invites the candidate to challenge the status quo and demonstrates that your organisation values divergent thinking. Candidates who can thoughtfully articulate how they’d expand the team’s capabilities show confidence and strategic awareness.

Seeing these principles in action makes implementation clearer.

Each interviewer tests specific leadership principles like “Ownership” or “Bias for Action.” For Ownership, they might ask: “Tell me about a time when you went outside your area of responsibility to help the company.”

What makes it effective: a certified Bar Raiser from a different department has absolute veto power, separating hiring decisions from urgent vacancy pressures. When your team desperately needs someone to start, objectivity suffers. Amazon’s system prevents that compromise.

Instead of artificial whiteboard coding, candidates use their own laptop. In their “Bug Bash” exercise, candidates access a GitHub repo with a faulty test case and must find and fix the bug.

This tests the ability to read others’ code and debug-far more relevant than reciting algorithms from memory. Work sample approaches like this have a validity coefficient of 0.54, making them one of the most accurate predictors of engineering performance.

At 80Twenty, we’ve adapted similar role-specific exercises for marketing and creative positions. Asking a content strategist to audit three pieces of existing content reveals more about their thinking than any number of behavioural questions.

Without a scoring system, recency bias and the halo effect distort your assessment. The last candidate seems freshest. The one who shared your university affiliation gets unconscious bonus points.

Use BARS (Behaviourally Anchored Rating Scales) with specific behavioural descriptions for each level.

Example for “Communication”:

• 1 (Insufficient) = Interrupts others, argues aggressively
• 3 (Competent) = Expresses ideas clearly, listens to feedback
• 5 (Excellent) = Synthesises complex ideas into simple terms, actively seeks dissenting opinions

The key tactical detail: score horizontally rather than vertically. Rate one question across all candidates before moving to the next question, rather than scoring one complete candidate at a time. This reduces the halo effect-where your overall impression of someone colours your assessment of their individual answers.

Document specific examples that justify each score. “Good communication skills” is useless for decision-making. “Explained technical concepts using analogies, asked clarifying questions before responding, acknowledged areas of uncertainty” provides concrete evidence.

Legal compliance isn’t optional, but it’s not the only reason to avoid certain questions.

Don’t ask about family plans, age, national origin, or religious beliefs. Beyond the legal risk, these questions introduce bias without providing job-relevant information.

Hypothetical puzzles or brain teasers predict nothing. Google’s data proved this conclusively, yet companies continue wasting interview time on questions that feel discriminating without actually discriminating between strong and weak candidates.

Questions that favour certain personalities over actual job competence create homogeneous teams. “Do you prefer working alone or in groups?” sounds reasonable but penalises introverts in a way that may not relate to the role’s requirements.

The result?

You hire people skilled at interviewing rather than people skilled at the job.

Question quality matters, but so does the sequence and timing.

Opening (5 minutes): Build rapport and explain the interview structure. Nervous candidates don’t showcase their best thinking, and surprises about format create unnecessary stress.

Core questions (40 minutes): Cover 4-6 behavioural questions with follow-ups. Resist the temptation to ask more questions superficially-depth beats breadth.

Work sample or scenario (15 minutes): If applicable to the role, include a practical exercise. This is where you see their process, not just their polished outcomes.

Candidate questions (10 minutes): What they ask reveals priorities. Someone who only asks about holiday allowance has different motivations than someone curious about your biggest strategic challenge.

Closing (5 minutes): Provide clear next steps and timeline. Leaving candidates uncertain about the process damages your employer brand and loses strong candidates to faster competitors.

It’s the result of relying on unstructured conversations rather than validated interview questions. By implementing structured behavioural questions, scoring responses objectively, and focusing on past performance rather than hypothetical scenarios, you can more than double your accuracy in predicting which candidates will succeed.

At 80Twenty, we’ve built our recruitment process around these evidence-based techniques, helping tech, e-commerce, and creative agencies across the US make faster, more accurate hiring decisions for specialist roles. If you’re ready to move beyond gut feeling and reduce the cost of mismatches.