Nielsen Global Media collects vast data on what consumers watch and buy, helping clients worldwide understand unmet needs, develop new products, and deliver them in an engaging way. As a Data Engineer at Nielsen, you will play a crucial role in developing and maintaining data pipelines, automating processes, and ensuring data quality. You'll be working with modern technologies like Python, SQL, Apache Spark, AWS, and Airflow to build scalable and efficient systems. Your role will involve collaborating with cross-functional teams to align development objectives with broader business goals, ensuring continuity and quality in data processing and infrastructure. This guide will walk you through the interview process for the Data Engineer position at Nielsen, providing valuable insights and preparation tips.

Submitting Your Application

The first step is to submit a compelling application that reflects your technical skills and interest in joining Nielsen as a Data Engineer. Whether you are contacted by a Nielsen recruiter or take the initiative yourself, carefully review the job description and tailor your CV according to the prerequisites.

Tailoring your CV may include identifying specific keywords that the hiring manager might use to filter resumes and crafting a targeted cover letter. Highlight relevant skills and mention your work experiences.

Recruiter/Hiring Manager Call Screening

If your CV happens to be shortlisted, a recruiter from the Nielsen Talent Acquisition Team will make contact and verify key details like your experiences and skill level. Behavioral questions may also be a part of the screening process.

In some cases, the Nielsen's data engineer hiring manager stays present during the screening round to answer your queries about the role and the company itself. They may also indulge in surface-level technical and behavioral discussions.

The whole recruiter call should take about 30 minutes.

Technical Virtual Interview

Successfully navigating the recruiter round will present you with an invitation for the technical screening round. Technical screening for Nielsen's data engineer role usually is conducted through virtual means, including video conference and screen sharing. Questions in this 1-hour long interview stage may revolve around Python, Pyspark, SQL queries, and data engineering principles.

Candidates might be asked to complete coding assignments related to product metrics, analytics, and data visualization. Demonstrating proficiency against aspects such as hypothesis testing, probability distributions, and machine learning fundamentals may also be important.

Depending on the seniority of the position, case studies or real-scenario problems may also be assigned.

Onsite Interview Rounds

Following a second recruiter call outlining the next stage, you’ll be invited to attend the onsite interview loop. Multiple interview rounds will be conducted during your day at the Nielsen office. Your technical prowess, including programming and ML modeling capabilities, will be evaluated against the finalized candidates throughout these interviews.

If you were assigned take-home exercises, a presentation round might await you during the onsite interview for the data engineer role at Nielsen.

Quick Tips For Nielsen Data Engineer Interviews

You should plan to brush up on any technical skills and try as many practice interview questions and mock interviews as possible. A few tips for acing your Nielsen interview include:

• Master PySpark and SQL: Nielsen's technical interviews often focus on PySpark and SQL. Ensure you understand how to optimize queries and troubleshoot issues.

• Know Big Data Tools: Familiarize yourself with Hadoop architecture, Spark application workflows, and data handling techniques to show your expertise.

• Be Prepared for Behavioral Questions: Nielsen values communication and problem-solving skills. Be ready to discuss your previous projects and how you handled challenges.

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

• How would you ensure data quality across different ETL platforms for PayPal's Southern African division? PayPal is conducting market research in Southern Africa, requiring data to be stored within each country's borders. The ETL pipeline connects PayPal’s data marts with the survey platform’s data warehouses, including translation modules for text data. As a consulting engineer, how would you ensure data quality across these ETL platforms?

• How would you explain what a p-value is 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 experiments or studies.

• What is the probability that a red marble was pulled from Bucket #1? Given two buckets with different distributions of red and black marbles, calculate the probability that a red marble shown to you was pulled from Bucket #1.

• What is the probability that two red marbles were pulled from Bucket #1? If your friend draws two red marbles sequentially with replacement from one of the two buckets, calculate the probability that both marbles came from Bucket #1.

• What is the probability that Amy wins the game by rolling a six first? Amy and Brad take turns rolling a fair six-sided die, with Amy starting first. Determine the probability that Amy wins by rolling a six before Brad does.

• How would you write a function to return all prime numbers up to N? Given an integer N, write a function that returns a list of all prime numbers up to N. If there are no prime numbers less than or equal to N, return an empty list.

• Create a function combinational_dice_rolls to list all possible combinations of dice rolls. Given n dice each with m faces, write a function combinational_dice_rolls to dump all possible combinations of dice rolls. Bonus: Can you do it recursively?

• Develop a function is_subsequence to check if one string is a subsequence of another. Given two strings, string1 and string2, write a function is_subsequence to find out if string1 is a subsequence of string2.

• Write a function to return all prime numbers up to a given integer N. Given an integer N, write a function that returns a list of all of the prime numbers up to N. Return an empty list if there are no prime numbers less than or equal to N.

• Create a function to add the frequency of each character in a string after each character. Given a string sentence, return the same string with an addendum after each character of the number of occurrences a character appeared in the sentence. Do not treat spaces as characters and exclude characters in the discard_list.

• Write a function sorting to sort a list of strings in ascending alphabetical order from scratch. Given a list of strings, write a function sorting to sort the list in ascending alphabetical order without using the built-in sorted function. Return the new sorted list rather than modifying the list in-place. Bonus: Aim for a solution with (O(n \log n)) complexity.

• What is the difference between XGBoost and random forest algorithms, and when would you use one over the other? Explain the key differences between XGBoost and random forest algorithms. Provide an example scenario where one algorithm would be preferred over the other.

What is the average salary for a Data Engineer at Nielsen?

Q: What is the interview process like for a Data Engineer position at Nielsen? The interview process typically consists of multiple rounds, including a coding assessment (often involving PySpark and SQL), technical interviews focused on projects and data engineering concepts, and HR discussions. Depending on your experience level, you might also need to complete a project or coding task as part of the evaluation.

Q: What technical skills are most important for a Data Engineer role at Nielsen? For a Data Engineer role at Nielsen, proficiency in Python or Scala, SQL, and big data processing tools like Apache Spark is essential. Experience with cloud services, particularly AWS, orchestration tools like Apache Airflow, and knowledge of data warehousing principles are also crucial.

Q: What kind of work environment and culture can I expect at Nielsen? Nielsen promotes a collaborative and inclusive work environment, encouraging employees to think big and continuously improve. They are committed to diversity and provide numerous opportunities for career growth, enabling your best to power their future.

Q: What are some common challenges faced during the interview process at Nielsen? Candidates often mention the technical rigor of the interviews, with a strong emphasis on PySpark, Spark optimization techniques, and data engineering fundamentals. Handling questions on big data architecture, cloud services, and solving coding problems effectively are key to success.

Q: How can I best prepare for a Data Engineer interview at Nielsen? To prepare effectively, practice common data engineering interview questions, review your knowledge in PySpark, SQL, and cloud technologies. Use Interview Query to access tailored practice questions and mock interviews to enhance your readiness.

Interviewing for the Data Engineer position at Nielsen presents a unique blend of technical challenges and opportunities for growth. Candidates often navigate through a series of rounds that test their proficiency in PySpark, SQL, cloud technologies, and data manipulation concepts. While the process may sometimes seem delayed or rushed, with some experiences reporting lack of feedback, it highlights the high standards Nielsen sets for its team members. If you're gearing up for this endeavor, Interview Query's Nielsen Interview Guide offers a wealth of insights and sample questions to help you prepare effectively. This guide covers various aspects of the interview process and provides resources tailored for roles like software engineering and data analysis. At Interview Query, we equip you with the knowledge and confidence to tackle any Data Engineer interview challenges. Check out our company interview guides for thorough preparation, and feel free to reach out with any questions. Good luck with your interview!