How to Prepare for a Data Analyst Technical Interview
If you're applying to a data analyst role at one point during the interview process you'll probably have a take home assessment or a technical interview (maybe even both). This interview usually comes after your first initial interview with the hiring manager. In this article, I'll be giving strategies and practical tips to ace your data analyst technical interview. But first let's define a technical interview.
Disclaimer: I am not a hiring manager and do not work in HR. This is all from my personal experience and research I've done.
What is a Technical Interview?
It's an interview to assess your technical ability, personality, and problem solving abilities for a role. A few things the company is looking for:
Strong technical knowledge (specific to the job description)
An understanding of how you think and problem solve
Assessing your analytical skills
What Skills are They Assessing?
For data analyst roles these are the most common skills asked for in the job posting:
These are the skills they will likely assess during the technical interview. However, it's important to note that the focus of the interview will typically be on one specific skill (rarely more than one). Meaning they'll focus on SQL questions or Excel concepts. I've personally had a Tableau and Excel technical interviews (at two separate companies).
Types of Questions:
Knowing what to expect during your technical interview can improve your performance. Here are some common question types you might be asked:
While I did say that technical interviews typically focus on a skill or two. Some interviewers may ask broader questions about statistics or data analysis concepts. Here are some examples of the type of 'explain' questions they may ask:
Statistics - define the following terms: normal distribution, outlier, or statistical model.
Data analysis - "what is quantitative data vs. qualitative data" or "explain a time series analysis".
Problem Solving Questions
These questions are when an interviewer asks you how you would approach a problem. Here are some types of questions I've been asked:
Example Dataset - They give you an example dataset from their company and ask how you would analyze X,Y,Z. They may want you to explain your answer using a specific tool like "how would you explore our customer sales table in SQL ?".
Company Specific - Or they may ask a more general question related to common data the company sees like "how would you find out which one of our sales person's has the highest sales for quarter 2?".
Both of these focus on how you approach a challenge and are assessing your problem solving ability.
Conceptual Questions about a Skill
These questions are testing your knowledge on broad concepts for that specific skill. Below are two types of conceptual questions I've been asked for two different skills:
Excel - "Explain to me what pivot table is" and "what does a VLOOKUP do?".
SQL - "What is the difference between a LEFT JOIN and an INNER JOIN?".
These questions are not asking about a specific problem to solve but rather your general understanding of a concept.
Specific Problems to Solve
These are questions like the ones you see in practice sites (e.g. Hackerrank). During these you'll have to demonstrate your ability with a specific skill. This could be writing a SQL query or an Excel formula to solve a problem. These are generally straight forward and have a correct answer (there may be multiple ways to get it). Below are 3 example types of questions I've gotten during SQL technical interviews:
Identifying Errors - "Identify the errors in the query. It should return X,Y,Z."
Editing an existing query - "Edit the query to show revenue by month instead of week."
Write a query to do X - "Write a SQL query to get the third-highest salary of an employee from employee_table?"
How to Practice
Now how do you practice for technical interviews?
Practice Questions on Sites
For specific tools like SQL there are websites that provide practice problems like Hackerrank, DataLemur, or Stratascratch. You can also look up practice problems on Youtube or find courses on Coursera or Udemy that have practice problems. Check out the resources I linked below for some specific Youtube videos and courses I found helpful.
Mock interviews are great for practicing your interviewing skills and receiving feedback. You can join communities like Data in Motion where they have experienced data professionals offer advice or give mock interviews. You can also network with other professionals on LinkedIn. See if anyone is willing to go through a mock interview with you. I'd suggest doing this with people who you've built a relationship with. Meaning, don't ask people right away if they can give you a mock interview.
I've had three mock interviews so far. One was with a member of the Data in Motion community who gave me a SQL technical interview. The other two were with connections I made on LinkedIn, focusing more on "behavioral interviews"
Real Interview Experience
Finally the best way to practice is to actually go through a technical interview. Your first technical interview is always nerve wracking and you may not do well. That's okay. Take a few notes and after your interview think about what you could've done to improve. Or if you can, ask your interviewer for feedback on your performance/answers.
I'll be honest my first technical interview did not go well. I was not prepared. Since then I've improved by: practicing questions and reviewing concepts beforehand; and researching the company and role. It takes time and practice to get better at technical interviews.
3 Tips to Help You During Your Interview
Below are three tips to help you succeed in your technical interviews:
Think out loud - the company/hiring manager wants to learn about how you think and problem solve. You want to explain your thought process behind your answer. If you don't know the answer you can talk through what steps you want to do. Like "I would want to do exploratory analysis using SQL first and then...".
Ask questions - when in doubt, ask questions. If you don't know what the interviewer is looking for, ask. It'll help you understand the question. And show your interviewer you're willing to ask and clarify if you don't understand something, an important skill to have.
Breathe - It's okay to be nervous. If you're having a hard time or your brain isn't working. Take a moment to breathe and center yourself. I like to take a drink of water to give myself a pause to think
Technical interviews are part of the interview process for data analyst roles. The best way to prepare is to practice beforehand (mock interviews, specific questions), research the company, and familiarize yourself with general concepts related to the skills they asked for. During the interview you want to take time to explain your reasoning and ask questions if you need clarification. It's okay if your first technical interview doesn't go well, we all start somewhere. The best thing to do is to take a moment and then move on and do better next time. Remember to focus on specific skills, problem-solving ability, and your overall analytical skills.
Below are more resources related to doing well in a data analyst technical interview. I used some of these for my research for this post:
Top 5 Data Analyst Interview Mistakes from Alex The Analyst
how I CRUSH Data Analyst Technical Interviews from Shashank Kalanithi
👩💼 How to Ace Data Analyst Interviews // Prepare With Me ft. Alex the analyst from Thu Vu data analytics
Can You Pass This Excel Interview Test? from Kenji Explains
Analyze a User's Posts - Data Analyst SQL Mock Interview from Exponent
SQL interview questions and answers | Entry level data analyst interview from Aaron Oliver