Top 17 Interview Questions to Ask to Find the Best Machine Learning Engineer

Job interviews aren't just nerve-wracking for candidates—they can make even experienced employers sweat a little, too, especially when you're hiring for a crucial role like a machine learning engineer. 

With machine learning (ML) reshaping how businesses operate, hiring the right ML engineer is becoming increasingly critical. Asking targeted interview questions is key to properly evaluating a candidate's capabilities and fit for your project and team. By choosing strategic interview questions, you can assess not only their technical skills but also their problem-solving abilities, adaptability, and communication skills. 

This guide offers insights into the skills to look for as well as 17 interview questions for ML engineers to help you identify the top talent that will move your business in the right direction.

What to Look for When Interviewing a Machine Learning Engineer

The World Economic Forum ranks machine learning engineers among the top five jobs of the future thanks to rapidly rising demand and their growing impact on business innovation. 

Hiring the right candidate is critical, not only because they’ll directly shape your company's technological capabilities but also because securing strong ML talent gives your business a significant competitive edge.

When interviewing a machine learning engineer, having a clear understanding of the skills to evaluate can make your decision-making process significantly more focused and successful. 

Here’s what to look for:

• Proficiency in data structures and algorithms: These skills are essential for designing, building, and deploying efficient and scalable ML systems.
• Strong problem-solving skills: Creative problem-solving is incredibly valuable in advanced machine learning, enabling ML engineers to successfully adapt when facing unexpected challenges, unusual datasets, or novel scenarios.
• Deep knowledge of ML concepts and frameworks: Understanding core ML paradigms (such as supervised and unsupervised learning) and key algorithms (like decision trees and neural networks) as well as familiarity with frameworks like TensorFlow or PyTorch indicate practical readiness.
• Understanding of system design and architecture: Knowledge of data pipelines, model training and evaluation, model deployment, and infrastructure is essential for developing ML solutions that will integrate effectively with your existing technology stack and scale as your business grows.
• Strong coding skills: Proficiency, particularly in Python, Java, and C++, is key, as most ML projects heavily depend on clear and efficient coding.
• Experience with data manipulation and processing: Candidates should be able to handle raw data confidently, cleaning, transforming, and preparing datasets effectively for accurate modeling.
• Knowledge of statistical and mathematical software: Familiarity with software like R or MATLAB gives ML engineers the confidence to tackle advanced analytical tasks, supporting their ML decisions with solid statistical evidence.

Finally, always explore past project experience to gauge practical expertise, as it's often the strongest indicator of their ability to contribute effectively from day one.

17 Machine Learning Interview Questions to Ask Candidates

When interviewing potential machine learning engineers, targeted questions help you cut through surface-level responses and uncover genuine expertise. 

These interview questions can help you effectively identify candidates who stand out technically, demonstrate exceptional practical skills, and fit well with your company’s culture.

Recruiter-recommended questions

These initial questions are favorites from our recruiting team and are particularly effective at highlighting a candidate's passion, adaptability, and communication skills.‍

1. How do you stay updated on advancements in AI and machine learning?

What it reveals: Their answer shows how proactive and committed they are to continuous learning. Whether they're reading industry research papers, attending conferences, or engaging in industry communities, the best engineers are naturally curious.‍

2. What types of machine learning models have you worked with, and can you describe a recent project where you built and deployed a model?

What it reveals: You'll gauge their practical experience, from training to deployment, and their ability to clearly communicate complex technical processes to colleagues or stakeholders.

3. How do you handle situations where stakeholders don't fully understand AI's capabilities or limitations?

What it reveals: This question assesses the candidate's soft skills, particularly their ability to set realistic expectations, manage relationships, and clearly articulate technical limitations without losing trust.

4. What aspect of machine learning excites you the most and why?

What it reveals: The answer to this question can indicate whether the candidate has a genuine interest in ML rather than just salary-driven motives for applying for the job, helping you spot alignment with your company's projects and culture.

If you’re struggling to find candidates who tick all these boxes, consider partnering with a recruitment agency that specializes in finding ML talent. They can take the pressure off of your internal recruitment team by providing pre-vetted candidates who meet your requirements. 

Essential technical questions for evaluating machine learning skills

The following questions, asked in technical interviews, are aimed at assessing a candidate’s deeper technical knowledge and competence in core machine learning concepts.

5.  What is the bias-variance tradeoff, and why does it matter?

What it reveals: Their grasp of foundational ML concepts, crucial for building effective and reliable models.

6.  Can you walk me through your process for hyperparameter tuning? What methods do you prefer?

What it reveals: Their technical rigor and practical understanding of how to optimize models efficiently.

7.  How do you validate your machine learning models to guarantee accuracy?

What it reveals: Whether they have a systematic, disciplined approach to measuring and delivering model effectiveness.

8.  How would you manage missing or inconsistent data in your projects?

What it reveals: Their practical approach to common, real-world data issues, demonstrating adaptability and problem-solving ability.

9.  Can you explain cross-validation and its significance in machine learning?

What it reveals: A deep technical understanding of machine learning fundamentals as well as their ability to make sure that models perform well beyond training environments.

10.  Describe one of the most challenging machine learning problems you've faced. How did you resolve it?

What it reveals: Their problem-solving methods, creativity under pressure, and practical resilience when confronting difficult issues.

Practical and industry-relevant questions

These questions help uncover practical knowledge that’s important for the successful integration and scaling of ML solutions within your business.

11.  Which tools or frameworks do you prefer for data preprocessing and why?

What it reveals: Indicates hands-on familiarity with essential data preparation tools, critical to any ML project’s success.

12.  What steps do you take to deploy a machine learning model into a production environment?

What it reveals: Gauges practical skills and direct experience in implementing models, important for real-world applications.

13.  How do you make sure your machine learning models are scalable and maintain performance as the dataset grows?

What it reveals: Highlights strategic foresight and experience managing growth, ensuring the longevity of your ML solutions.

14.  Describe your experience monitoring deployed ML models. How do you track performance and manage drift?

What it reveals: Reveals their awareness of model lifecycle management, critical for maintaining model effectiveness long-term.

Soft skills and cultural fit questions

Machine learning projects rarely happen in isolation—they’re collaborative efforts. Asking this set of questions can help you determine how well candidates are likely to integrate with your team dynamics and fit in with your company culture.

15.  Tell me about a project where you collaborated closely with engineers or data scientists. What was your role and what did you learn from it?

What it reveals: Highlights teamwork, communication skills, and their ability to integrate well within multidisciplinary teams.

16.  How do you stay on top of new developments in machine learning?

What it reveals: Indicates their motivation for continuous professional growth, which is essential in the rapidly advancing ML field.

17.  Describe a situation where you disagreed with a team member or stakeholder on a machine learning strategy. How did you handle it?

What it reveals: Provides insight into their conflict-resolution skills, emotional intelligence, and professional maturity.

Bonus: 3 Interview questions for remote ML engineers

Remote machine learning roles require candidates who bring more than just technical expertise. They also need to be self-motivated and adaptable and skilled at communication, time management, and virtual collaboration. These bonus questions will help you determine if a candidate has what it takes to succeed in a remote work environment.

1. How do you stay productive and organized when working remotely on machine learning projects?

What it reveals: Highlights a candidate's self-discipline, time-management abilities, and organizational skills, which are essential for productivity in remote work settings.

2. Which collaboration and communication tools do you prefer when working remotely?

What it reveals: Indicates the candidate’s experience collaborating virtually and their adaptability to your company’s existing remote workflow.

3. How do you approach troubleshooting technical challenges when your team is distributed across multiple time zones?

What it reveals: Provides insight into the candidate’s independence, problem-solving skills, and comfort level handling challenges that arise specifically in remote work environments.

Equipped with these questions, you’ll be able to accurately gauge a candidate’s fit and readiness to work independently in a remote ML engineer role.

Making Your Candidates Feel Comfortable

Remember, the purpose of an interview is to assess a candidate's skills and clearly understand their experience, not to catch them off guard and trip them up with obscure or overly complicated questions. 

Avoid questions designed purely to trick or confuse candidates, as this can create unnecessary pressure and doesn’t give you an accurate picture of their abilities. Keep niche topics relevant to your job description and let candidates know what to expect beforehand so they can come to the interview prepared. 

When you create a comfortable, conversational atmosphere, candidates can showcase their abilities, giving you a more accurate sense of how they'll perform as part of your team.

Final Thoughts

Finding the right machine learning engineer relies heavily on asking strategic, insightful interview questions. Instead of sticking with surface-level questions that provide limited insight, aim to dig deeper with focused questions about real-world experience, technical expertise, and soft skills. This approach will give you a clearer picture of each candidate’s strengths, Doing so provides a clear picture of each candidate’s strengths, helping you make confident hiring decisions.

To broaden your talent search, consider experienced nearshore ML engineers in Latin America. Nearshoring your ML talent can offer significant cost savings for US businesses while allowing your project teams to scale up and down as needed.

Great hiring also doesn't have to consume valuable time. If you'd prefer to focus on growing your business while letting someone else handle these detailed conversations, staffing and recruitment firms like Near can do the heavy lifting for you by connecting you with pre-vetted ML engineering candidates. 

Interested in learning how you can reduce hiring costs while still accessing top-tier ML talent? Check out our guide on How to Hire a Remote Machine Learning Engineer.