Interview Questions for Tableau & Power BI

Hiring new people onto your team can be a daunting and tedious task for a lot of managers. Since my current team had been doing lots of hiring, I posed the following question to Twitter, and I got some very thoughtful and interesting responses:

The best thing about the responses to this tweet were their depth and variety. Most folks that responded had done hiring before, and almost all of them were coming from different backgrounds, experiences, and industries. In this blog I’m going to summarize some of the common themes found in the responses to how interviewers assess a candidate’s capabilities during a interview. I framed the question from the perspective of a Tableau or Power BI manager, but most of the answers could be applied cross-functionally. I will break out the responses into those specific to Power, Tableau, and then those that are tool agnostic.

A couple of things to point out before we get into the questions. There were a couple of items that were mentioned more than twice. One was, where do people go when they get stuck or what sources in the community do they follow. Another one was to ask for an example of the interviewee’s work and then have them walk through it while describing their thought process. I though both of them were great questions, so here’s a lot more. Enjoy!

Power BI

Let’s start off with some of the questions that responders want to ask Power BI candidates.

  1. What’s is the difference between M and DAX and can you talk me through why you would use one versus the other? (Micah Dail)
  2. Who are you following (in-person or online) to get perspectives and approaches different than your own? (this was a common one, but credit Alex Powers)
  3. I ask them to share screen open Power BI Desktop, load the sample data. Make a bar chart, Remove the title, change the chart type (Power BI Tips)
  4. Explain the various storage modes and when you would use one over the other. How would you add a calculated column to a table? When would you use a dashboard vs report? Risks and benefits of custom visuals? How do you test and deploy to production with PBI? (Meagan Longoria)
  5. “What three things do you like the most about #PowerBI?”, followed up with, “What three things do you hate the most about #PowerBI?” (Jeff Weir)
  6. “Tell me why you would use a star schema vs a flat table as a data source. What are the advantages/disadvantages of either choice?” (Sawyer Nyquist)
  7. This might seem small, but I’d give them a few basic measures to create in Power BI – nothing to really test their technical skill – and see if they just key it in OneLongRunonFormulaExcelStyle or if they attempt to format it (indents, tabs, etc.). Speaks to readability. (Ed Hansberry)
  8. Describe difference between calculculated column vs measure, Dataflow vs dataset, what external tools do you use with Power BI? When would you distribute the report as an App vs Report directly, personal gateway vs enterprise gateway. (Sandeep Pawar)

Tableau

Although slightly different than the Power BI questions, a lot of them touched on some similar concepts as the Power BI questions.

  1. If external, what’s the most recent version they’ve used? Do you have a Tableau Public profile or examples? Not required, just nice to see. Even with a pretty profile, that doesn’t mean they can build scalable business dashboards. (Will Perkins)
  2. What is the difference between continuous and discrete dates? Explain the behavior of Top N with regards to dimensions and context filters? (Aman Gulati)
  3. I like to test the candidates on basics. So some tricky questions on “Order of Operation” and steps on performance enhancement. There is still a big confusion on blue and green pills. 90% of time I have got the incorrect answer on that. (Priyanka Dobhal)
  4. One I really liked being asked was to walk through the thought process behind a viz on my Tableau Public page that the interviewer selected. (Kate Brown)
  5. Do you have a portfolio? Show me your @tableaupublic profile. (Alexander Mou)
  6. Well I always asks WHY instead of WHAT … like What is context filter or dynamic parameters can be asked as why do we use Context filter and Dynamic Parameters. (Sameer Vaghela)
  7. Explain a Fixed Level of Detail calculation.

Tool Agnostic

Although a lot of responses were specific to Tableau or Power BI, there were a lot of great interview questions or activities that apply to any BI platform. Here are some of those responses:

  1. I ask them what’s their favorite sites to visit – it helps me gauge the extent that they are seekers of knowledge. (Candra McRae)
  2. Tell me about a situation with bad requirements and how you addressed it? Tell me about when you failed and what you learned from it? What is something you’re proud of you’ve done professionally and why? (Will Perkins)
  3. What additional feature would improve your favorite tool the most? (Steve Fenn)
  4. One thing I typically ask is about their previous work and how data was packaged for them in previous roles? What I am really asking is if they pre-aggregated the data or if they would create calcs in the tools. Neither is wrong but sometimes a job requires one over the other. (Cesar Picco)
  5. I don’t like asking questions. I give a questionable chart to the person and ask he/she to describe what is good/bad and what would she/he do to improve it (and send us the new chart in the tool of their choice) (Rodrigo Calloni)
  6. I like to ask 1) how they learn new tools 2) how do you engage with your users to make sure you build the right thing 3) if they could work only on data presentation or only on data structuring which would they choose. (Alex Dupler)
  7. I would ask what their strategy would be to maintain their workbooks – strategy as new versions are released, strategy as to how they will manage existing workbooks and new ones. Just generally interested in their thought process and what their considerations are. (Donabel Santos)
  8. What type of community resources do you utilize to stay up-to-date on trends or build your skills? (for Power BI it’s great to hear the Microsoft Power BI Blog, SQLBI, Guy In A Cube, local user groups, etc.) (Barrett Studdard)
  9. Not sure I ask any technical questions, give them a viz exercise using superstore to showcase their ability to tell data driven stories & drive insights, then I focus the conversational part on their values and behaviors to assess empathy, curiosity & their openness to feedback. (Simon Beaumont)
  10. My typical question is what do you hate about a tool. If you have used a tool for a while, you would have had many nights cursing the lack of a feature or something that you think was poorly designed etc… Plus, a lot if people don’t expected the question, so no canned responses. (Toan Hoang)
  11. I always ask what their favourite features or aspects of use are and why. And also the least favorite. Allows some expression and ability to show depth of skills. (Paul Banoub)
  12. I show them 1 calculation, then I say “pretend I’m your customer and I’ll brb to make coffee, you have 5 minutes to tell me how to optimize this calculation and there’s a few places to optimize” when I get back from 5 minutes you can start.” (Tyler Garrett)
  13. “Where do you go when you’re stuck?” “Which community resources do you stay up to date on?” I personally hate live tech screenings. Some of the most brilliant tech minds need peace, quiet, and 7 open tabs to operate. If they’re intelligent, passionate, and resourceful, hire them. (Chris Shanku)
  14. My report takes forever to load….what can you do to improve it? – Nobody uses the reports….How can we improve that? (Nick Snapp)

I hope that this blog post was helpful for both interviewers seeing what other people were asking candidates as well as for interviewees who might being wondering what questions could arise during their interviews. The interaction from all communities was amazing on this, thanks to all who participated and gave their input on my question.

If you have any feedback or items to add, feel free to DM me at @jsbaucke or email me at spencer.baucke@tessellationconsulting.com.

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