You have 45 minutes. Sitting across from you is someone you've never met before. After this conversation, you need to decide whether they'll be part of your team for the next few years. No pressure.

The reality is: Many managers and recruiters rely on their gut feeling in this situation. The problem? It doesn't work. Current research shows that unstructured interviews have only limited predictive power for future job performance. In other words: That good feeling you have after the conversation says little about whether the person will actually succeed.

In this guide, you'll learn how to conduct job interviews professionally. You'll discover why structured interviews deliver demonstrably better results, how to properly apply the STAR method, and which strategies reduce unconscious bias. At the end, you'll find a checklist you can use directly in your next interview.

What Makes a Good Job Interview?

A good job interview isn't a pleasant chat. It's a diagnostic tool that helps you find the best person for a position. That means: You need structure, clear criteria, and the right questions.

The Dilemma: Gut Feeling vs. Objectivity

You know the feeling: After an interview, you instantly have an impression. Likeable. Competent. A good fit for the team. Or not. The problem is that this feeling often says more about you than about the candidates.

Affinity bias describes the tendency to favor people who are similar to us. Someone who went to the same university, shares the same hobbies, or communicates similarly automatically seems more likeable. This has nothing to do with professional qualifications.

Then there's the halo effect: One positive trait overshadows the entire perception. Because someone speaks eloquently, you unconsciously rate their professional competence higher as well. Conversely, a stumble at the beginning causes you to only see mistakes afterward.

Researcher Stephanie Wondrak (2014) defines unconscious bias as unconscious cognitive distortions and erroneous tendencies in perception, memory, and judgment. These distortions happen automatically, without you even noticing.

Scientific Findings on Interview Validity

The research is clear: The way you conduct an interview significantly determines the quality of your decision.

Validity describes how well a method measures what it's supposed to measure. For job interviews, this means: How reliably can you predict future job performance?

A groundbreaking meta-analysis by Sackett et al. (2022) examined the predictive power of various selection methods. The result: Structured interviews achieve a validity of r=0.42. This means that 42% of the differences in later job performance can be explained by the structured interview.

That might not sound like much, but it's actually remarkable. For comparison: Unstructured conversations, where you spontaneously ask whatever comes to mind, perform significantly worse.

Structured vs. Unstructured Interviews: What the Research Says

The difference between a structured and an unstructured interview is fundamental. It determines whether you're comparing apples to apples or apples to oranges.

Validity Comparison: Which Method Performs Better?

The meta-analyses by Schmidt and Hunter (1998, updated 2016) are considered the standard work in personnel selection. Their results show clear differences:

A structured interview follows a fixed process: All candidates receive the same questions in the same order. Responses are evaluated according to defined criteria. This makes conversations comparable.

An unstructured interview, on the other hand, flows like a free conversation. You ask whatever comes to mind and evaluate based on feeling. The result: Every conversation is different, and in the end, you're not comparing candidates—you're comparing your own spontaneous impressions.

The Multimodal Interview According to Schuler

Professor Heinz Schuler developed the multimodal interview in 1992, which combines structured elements with flexible conversation phases. It achieves high validity with good acceptance because it still feels natural despite standardization.

The model combines various conversation elements: small talk to break the ice, behavior-based questions about past situations, situational questions about hypothetical scenarios, and room for free self-presentation. This gives you a comprehensive picture without sacrificing comparability.

The 5 Phases of a Professional Job Interview

A good conversation needs a clear structure. The optimal duration is 45-60 minutes. This gives you enough time for depth without losing concentration.

Phase 1: Preparation – Requirements Profile and Question Catalog

Preparation determines success. Before you conduct the first interview, you need a clear requirements profile.

A good requirements profile defines must-have and nice-to-have competencies. It describes observable behavior for each competency and establishes evaluation criteria with a scale. Create it together with the hiring department. This way, you know exactly what to ask about in the interview and what to look for.

Based on this, develop a question catalog with 8-12 STAR questions. Each question should test a specific competency from the requirements profile.

Phase 2: Welcome and Opening (5 Minutes)

Start with brief small talk to reduce nervousness. Introduce yourself and everyone present. Explain the interview process so candidates know what to expect.

Create a pleasant atmosphere. Offer water. These few minutes are crucial for a good candidate experience—even if you end up declining.

Phase 3: The Interview – Applying the STAR Method Correctly (25-30 Minutes)

The main part follows the structured question catalog. This is where the STAR method comes into play, which we'll cover in detail in the next chapter.

Important: Ask each person the same questions in the same order. Only then will the answers be comparable later.

Phase 4: Company Presentation and Questions (15 Minutes)

Now it's your turn. Present the company, team, and position. Be honest about challenges. Candidates who start with false expectations will leave quickly.

Allow time for questions. The questions candidates ask reveal a lot about their motivation and preparation.

Phase 5: Closing and Follow-up (5 Minutes + Afterward)

Explain the next steps and timeline. Thank them for their time.

Immediately after the interview: Evaluate each competency individually using your evaluation form. Don't wait until after all interviews. The fresher the impressions, the more accurate the evaluation.

The STAR Method: Asking Behavior-Based Questions Correctly

The STAR method is a behavior-based interview technique based on a simple principle: Past behavior is the best predictor of future behavior.

STAR stands for:

• Situation: What was the context?
• Task: What was the task or challenge?
• Action: What did the person do?
• Result: What was the outcome?

How to Formulate STAR-Compliant Questions

A good STAR question always starts with a prompt to describe a specific past situation. Avoid hypothetical questions like "What would you do if...?" These show how someone claims they would act, not how they actually do act.

Example formulations:

• "Describe a situation where you had to complete a project under time pressure."
• "Tell me about a conflict in your team and how you handled it."
• "Give me an example of a situation where you made a mistake and learned from it."

10 Example Questions for Different Competencies

Avoiding Common Mistakes with the STAR Method

The most common mistake: You settle for vague answers. If someone says "I'm generally very good at teamwork," follow up: "Can you give me a specific example?"

Another mistake: You ask leading questions like "You're certainly good at handling stress, right?" This provokes socially desirable answers instead of honest self-assessment.

Unconscious Bias in Job Interviews: How to Make More Objective Decisions

Unconscious biases influence every hiring decision. This isn't a weakness—it's human. The first step toward improvement is awareness.

The Most Common Bias Types in Interviews

Confirmation bias describes the tendency to search for information that confirms our preconceptions. You have a positive first impression? Unconsciously, you only notice the positives afterward and ignore warning signs.

With the halo effect, one positive trait overshadows the entire perception. Conversely, a negative detail leads to the horn effect: One stumble at the beginning colors the entire conversation.

Affinity bias causes you to favor people who are similar to you. Same university, same hobbies, similar communication style? Sympathy arises automatically but has nothing to do with job suitability.

5 Strategies for Bias Reduction

1. Structured interviews with a fixed question catalog: Same questions for everyone reduce the influence of spontaneous impressions.
2. Diverse interview teams: Different perspectives balance out individual biases. The multiple-eyes principle works.
3. Objective evaluation forms: Define criteria and scales before the interview. Only evaluate what's observable.
4. Create awareness: Those who know their own biases can actively counteract them. Training helps.
5. Objective data foundation before the interview: Assessment tools provide information independent of resumes and first impressions.

Objective Assessments as a Complement

Research shows: The combination of structured interviews and assessments achieves the highest overall validity. The logic is simple: Two independent data sources provide a more complete picture than one alone.

Objective assessment tools like Aivy enable data-based decisions before the interview. The platform uses game-based assessments that are scientifically validated and measure competencies independent of the resume.

The result: You enter the conversation with a strengths profile and can ask more targeted questions. Instead of general impressions, you know where to dig deeper.

Companies like OMR use this approach specifically for more objectivity. People Lead Kaya Kruse reports: "Aivy works. We reduce bias, gain more objectivity in hiring, and strengthen diversity in the long term." The concrete result: Candidates were hired who would have been rejected based on their CV.

Evaluation and Decision: From Conversation to Selection

The conversation is over. Now begins the second critical part: objective evaluation.

Creating and Using an Evaluation Form

A structured evaluation form is indispensable. It contains all competencies from the requirements profile and a clear scale, for example from 1 to 5.

Evaluate each competency individually immediately after the interview. Document concrete observations, not interpretations. Instead of "seemed insecure," note "interrupted the sentence three times, avoided eye contact."

Important: Only compare after all interviews. Otherwise, the first conversation influences your standards for all that follow.

Multiple-Eyes Principle: Why Diverse Interview Teams Matter

Different people perceive different things. A diverse interview team balances out individual biases.

Ideal: At least two people conduct the interview, or there are multiple interview rounds with different interviewers. Their evaluations are only compared after everyone has evaluated individually.

Combining Interviews and Assessments

You make the best decision when you combine multiple independent data sources. Schmidt and Hunter's research shows: Structured interview (r=0.51) plus aptitude test (r=0.54) yields the highest overall validity.

An assessment before the interview provides an objective data foundation and enables more targeted questions in the conversation. You know where strengths lie and can address development areas specifically.

Case Study: How Companies Have Optimized Their Interview Process

Theory is important. But what does it look like in practice?

Lufthansa fundamentally restructured their recruiting process. Instead of focusing early on the resume, the airline relies on objective diagnostics before the interview. The results are convincing: 81% candidate satisfaction, 96% hit rate in predicting suitability compared to the elaborate in-house assessment, and 100+ minutes of saved testing time per applicant.

Susanne Berthold-Neumann from Lufthansa explains the approach: "We look at the documents late because they only show a small part of the person and say little about whether someone has the competencies for future challenges."

Mid-sized companies also benefit. Callways restructured their recruiting process and reports noticeably better conversation quality. Co-CEO Achim Reinhardt: "Resumes and certificates say little about future performance. With Aivy, we see what technology can really achieve: an intuitive tool that makes us significantly more effective." The conversations are "significantly better and more to the point," and the investment pays off from day 1.

The complete Lufthansa success story shows in detail how objective assessments and structured interviews work together.

Checklist: Conduct Job Interviews Professionally

You can use this checklist right away:

Before the Interview:

• Requirements profile created with hiring department
• Question catalog with 8-12 STAR questions prepared
• Evaluation form with scale defined
• Resume and application documents reviewed
• Assessment results reviewed (if available)
• Interview team coordinated

During the Interview:

• Small talk to break the ice (max. 5 minutes)
• Process explained
• All STAR questions asked in the same order
• Followed up on vague answers
• Notes taken
• Time given for questions
• Next steps explained

After the Interview:

• Evaluated immediately (don't wait!)
• Each competency rated individually
• Observations documented, not interpretations
• Coordinated with interview team
• Candidate informed promptly

Frequently Asked Questions (FAQ)

What questions am I not allowed to ask in a job interview?

Prohibited questions include those about pregnancy and family planning, religious affiliation, political beliefs, ethnic origin, sexual orientation, union membership, and health status (unless directly relevant to the job). These questions violate anti-discrimination laws.

How long should a job interview last?

The optimal duration is 45-60 minutes. This allows for: 5 minutes of greeting, 25-30 minutes of interview with STAR questions, 10 minutes of company presentation, 10 minutes for questions, and 5 minutes for closing. For leadership positions, it may take longer.

Should I conduct video interviews differently than in-person interviews?

The basic principles remain the same. Pay attention to good lighting and a neutral background, maintain stable eye contact with the camera (not the screen), and plan for slightly more conversation pauses. A technical check beforehand is essential. Incidentally: Initial screening calls by phone can even reduce bias since visual impressions are eliminated.

What makes a good requirements profile for interviews?

A good requirements profile defines must-have and nice-to-have competencies, describes observable behavior for each competency, and establishes evaluation criteria with a scale. It should be created together with the hiring department. This way, you know exactly what to ask about in the interview and what to look for.

What are the most common mistakes employers make in job interviews?

The five most common mistakes are: no preparation or guide, talking too much instead of listening, spontaneous questions instead of a structured catalog, gut feeling instead of defined criteria, and no follow-up or documentation. Each of these mistakes significantly reduces the quality of the hiring decision.

How do I optimally combine job interviews with other selection methods?

You achieve the highest predictive validity through combination: structured interview plus aptitude test plus optionally a work sample. An assessment before the interview provides an objective data foundation and enables more targeted questions in the conversation.

Conclusion: Better Conversations Lead to Better Decisions

The research is clear: Structured interviews with the STAR method significantly outperform unstructured conversations. Those who additionally apply bias strategies and integrate objective assessments make demonstrably better hiring decisions.

The key points summarized:

• Structured interviews have a validity of r=0.42 to r=0.51, significantly higher than unstructured conversations
• The STAR method examines past behavior—the best predictor of future behavior
• Unconscious biases like confirmation bias, halo effect, and affinity bias influence every decision
• Objective evaluation forms, diverse interview teams, and assessments demonstrably reduce bias
• The combination of structured interview and aptitude test achieves the highest overall validity

The next step is up to you. Use the checklist for your next interview. Create a question catalog with STAR questions. And consider how objective assessments can complement your process.

Tools like Aivy support you in making data-based decisions, reducing bias, and improving the quality of your conversations. The result: fewer bad hires, happier teams, and fairer hiring.

Sources

• Sackett, P. R., Zhang, C., Berry, C. M., & Lievens, F. (2022). Revisiting meta-analytic estimates of validity in personnel selection: Addressing systematic overcorrection for restriction of range. Journal of Applied Psychology.
• Schmidt, F. L., & Hunter, J. E. (1998, updated 2016). The validity and utility of selection methods in personnel psychology: Practical and theoretical implications of 85 years of research findings. Psychological Bulletin.
• Schuler, H. (1992). Das multimodale Interview. Diagnostica.
• Wondrak, S. (2014). Unconscious Bias: Definition and Fundamentals.