The Boston Consulting Group Data Engineer Interview Questions + Guide in 2024

The Boston Consulting Group (BCG) is a global management consulting firm known for pioneering strategy consulting over 50 years ago. BCG is recognized for continuously innovating and redefining industries, providing their clients with comprehensive solutions that deliver lasting impact.

If you’re considering joining BCG as a Data Engineer, you will become a key player in the North America (NAMR) People Analytics team. This role involves designing and building data infrastructures that support advanced analytics solutions. Your responsibilities will include developing ETL processes, ensuring data integrity, and deploying machine learning models.

In this Interview Query guide, we’ll provide insights into the interview process, commonly asked The Boston Consulting Group data engineer interview questions, and tips to help you succeed. Let’s dive in and prepare you for a successful interview experience at BCG!

The interview process usually depends on the role and seniority; however, you can expect the following on a The Boston Consulting Group data engineer interview:

Recruiter/Hiring Manager Call Screening

Once your application is shortlisted, you will be contacted by a recruiter from BCG’s Talent Acquisition Team. The recruiter will verify key details like your experiences and skill level. Behavioral questions may also be a part of this initial screening process, including questions like:

• Why BCG?
• Why consulting?
• What accomplishment are you most proud of?

This round typically takes about 30 minutes.

Technical Virtual Interview

If you pass the recruiter screening round, you will be invited for a technical screening round. This may involve a combination of coding, data engineering problems, and machine learning case scenarios.

Typical Components:

• Online Test: You might be asked to complete an online coding test, sometimes delivered through platforms such as Interview Query.
• First Technical Interview: Questions around ETL pipelines, SQL queries, and data systems.
• Second Technical Interview: More in-depth problems, possibly involving live coding or case interviews (e.g., system design, machine learning applications).

The questions can be quite challenging, so extensive preparation is recommended.

Onsite Interview Rounds

If you successfully navigate the technical virtual interview, you may be invited for onsite interviews, sometimes involving multiple rounds on the same day. These interviews evaluate your fit within the company culture and your technical capabilities.

Typical Components:

• Fit Interviews: These gauge how well you align with BCG’s values and work culture.
• Technical Interviews: Drill deeper into problem-solving skills. You may face more case interviews focusing on real-world scenarios.
• Business Problem Cases: Assess your ability to handle business problems with tests on business acumen, mental math, and structured thinking.

BCG Interview Preparation

BCG offers access to CaseCoach resources to help you prepare for the first and second-round interviews. It also assigns a buddy (an associate or consultant at the firm) who provides tips and insights and conducts mock interviews.

Typically, interviews at Boston Consulting Group vary by role and team, but commonly, Data Engineer interviews follow a fairly standardized process across these question topics.

1. How would you set up an A/B test for button color and position changes?

A team wants to A/B test multiple changes in a sign-up funnel, such as changing a button from red to blue and/or moving it from the top to the bottom of the page. How would you set up this test?

2. How would you forecast Facebook’s revenue for the next year?

An executive asks you to forecast how much revenue Facebook will make in the coming year. How would you approach this task?

3. How would you determine if a redesigned email campaign led to an increase in conversion rates?

An E-commerce store’s new-user-to-customer conversion rate increased from 40% to 43% after launching a new email journey. However, the rate was 45% a few months prior. How would you investigate if the redesigned email campaign caused the increase?

4. How would you ensure data quality across different ETL platforms for PayPal’s market research?

PayPal is conducting market research in Southern Africa, requiring data to be stored within each country’s borders. How would you ensure data quality across ETL pipelines connecting PayPal’s data marts with the survey platform’s data warehouses, including translation modules?

5. How would you conduct an experiment to test Uber’s new ETA range feature?

Uber is considering a new feature that displays an ETA range (e.g., 3-7 minutes) instead of a direct estimate. How would you conduct this experiment and determine if the results are significant?

6. Write a function min_distance to find the minimum absolute distance between elements in an array and return all pairs with that distance.

Given an array of integers, write a function min_distance to calculate the minimum absolute distance between two elements and return all pairs having that absolute difference. Ensure the pairs are in ascending order.

7. Write a query to select the top five most expensive projects by budget-to-employee count ratio, accounting for duplicate rows.

Given two tables, projects and employee_projects, write a query to select the five most expensive projects by budget to employee count ratio. Ensure to account for duplicate rows in the employee_projects table.

8. Write a function to simulate drawing balls from a jar.

Given a list jar with ball colors and a list n_balls with corresponding counts, write a function to simulate drawing a ball from the jar.

9. Design three classes: text_editor, moving_text_editor, and smart_text_editor with specific functionalities.

Design three classes: text_editor, moving_text_editor, and smart_text_editor. Each class should have specific methods for writing, deleting, and performing special operations on text.

10. Write a query to determine the top 5 actions performed during Thanksgiving week and rank them.

Given an events table, write a query to determine the top 5 actions performed during the week of Thanksgiving (11/22/2020 - 11/28/2020) and rank them based on the number of times performed. If two actions were performed equally, they should have the same rank.

11. What kind of model did the co-worker develop for loan approval?

Your co-worker developed a model that takes customer inputs and returns a decision on whether a loan should be given or not. What type of model is this?

12. How would you compare two credit risk models for predicting loan defaults?

Since personal loans are monthly installments, how would you measure the difference between two credit risk models within a specific timeframe?

13. What metrics would you track to measure the success of a new credit risk model?

Identify the key metrics you would track to evaluate the performance of a new model predicting loan defaults.

14. When would you use a bagging algorithm versus a boosting algorithm?

Compare two machine learning algorithms. In which scenarios would you prefer a bagging algorithm over a boosting algorithm? Provide examples of the tradeoffs between the two.

15. How would you detect firearm listings on a marketplace?

Design a system to automatically detect if a listing on your website’s marketplace sells a gun, given that selling firearms is prohibited by your website’s Terms of Service Agreement.

16. How would you design a model to map legal first names to likely nicknames?

As a data scientist at Facebook, you need to generate a machine learning model that maps the legal first name of a person to likely nicknames. How would you approach designing this model?

17. How would you tackle multicollinearity in multiple linear regression?

Explain the methods you would use to address multicollinearity when performing multiple linear regression.

18. How would you explain a p-value to someone who is not technical?

Explain the concept of a p-value in simple terms to a non-technical person, focusing on its role in determining the significance of results in hypothesis testing.

19. What is the probability that it’s actually raining in Seattle given your friends’ responses?

You call 3 friends in Seattle to ask if it’s raining. Each has a ²⁄₃ chance of telling the truth and a ¹⁄₃ chance of lying. All 3 say “Yes.” Calculate the probability that it is actually raining.

20. What is the probability of drawing three cards in increasing order from a shuffled deck of 500 cards?

Imagine a deck of 500 cards numbered 1 to 500. If you pick three cards one at a time, calculate the probability that each subsequent card is larger than the previous one.

21. How would you test if survey responses were filled at random by certain individuals?

You have survey data from multiple-choice questions. Describe how you would determine if some individuals filled out the survey randomly rather than truthfully.

22. What is the probability of a biased coin landing heads exactly 5 times out of 6 tosses?

Given a biased coin that lands heads 30% of the time, calculate the probability of getting heads exactly 5 times in 6 tosses.

You should plan to brush up on both technical and behavioral skills extensively. A few tips for acing your BCG interview include:

1. Familiarize with Data Systems and Tools: Understand the specific data systems and tools used at BCG, such as Snowflake Data Factory and dbt. Be ready to discuss your experience with SQL and NoSQL databases.

2. Practice Case Interviews: BCG emphasizes solving complex business problems. Use Interview Query to practice different case scenarios, focusing on business and technical aspects.

3. Understand BCG Culture: BCG values strong problem-solving skills and cultural fit. Be prepared to discuss why you want to join BCG and how your experiences align with the company’s goals and values.

What is the average salary for a Data Engineer at The Boston Consulting Group?

How long does the BCG hiring process typically take?

The entire hiring process can take 2-3 weeks, depending on scheduling and availability. Some candidates have reported a quick process, with stages completed within 2 weeks.

What qualifications are required to apply for the Data Engineer position at BCG?

Candidates should have a bachelor’s degree in Computer Science or a relevant field and 2-3 years of experience in a commercial setting delivering analytics solutions. Proficiency in SQL-based and NoSQL technologies, as well as Python, and experience with Agile methodologies are also required.

What kind of technical skills is BCG looking for in a Data Engineer?

BCG looks for skills in database management, data cleansing, and transformation, advanced data engineering practices, implementing analytics, and robust coding practices. Experience with tools like Snowflake, dbt, and Neo4j is highly valued.

Interviewing for the Data Engineer position at The Boston Consulting Group (BCG) is undoubtedly rigorous and challenging, designed to identify the best talent for their cutting-edge analytics needs.

If you want more insights about the company, check out our main Boston Consulting Group Interview Guide, where we have covered many interview questions that could be asked. We’ve also created interview guides for other roles, such as software engineer and data analyst, where you can learn more about BCG’s interview process for different positions.

You can also check out all our company interview guides for better preparation, and if you have any questions, don’t hesitate to reach out to us.

Good luck with your interview!