25+ Tableau Interview Questions to Prep For Your Next Role
How well do you know Tableau? These Tableau interview questions and answers will help you test your knowledge and further your career.
The questions are separated into the following topics:
- Tableau editions
- Creating your first visualizations
- Exploring Tableau
- Organizing and simplifying data
- Advanced visualization techniques
- Data connections
Last Updated November 2020
From beginners to skills needed for Certified Associate or Desktop Specialist certifications. Tableau 2018, 2019, 2020 | By Phillip BurtonExplore Course
The first topic, Tableau editions, covers a general awareness of Tableau’s products. Knowledge of the remaining topics is required as part of Tableau’s official Desktop Certified Associate certification. You can test yourself to see how close you are to passing this certification. You’ll also need to be familiar with many of these topics for Tableau’s Desktop Specialist certification.
On to the questions.
Can you name at least five different Tableau products?
There are many different Tableau software products, each with their strengths and disadvantages. These include:
- Tableau Desktop
- Tableau Prep
- Tableau Server
- Tableau Online
- Tableau Mobile
- Tableau Public
- Tableau Reader
What is Tableau Desktop and how much does it cost?
Tableau Desktop is the full creative program within the Tableau suite. You can use it to load data from hundreds of data sources; create visualizations, dashboards, and stories; and upload them to the cloud or save them to your hard drive.
It is part of the Tableau Creator package and, after a free trial period, the package costs around $70 per user per month.
What is Tableau Prep and how can you get it?
Tableau Prep is an additional part of the Tableau package. It allows you to get and transform data before it gets loaded into Tableau Desktop.
It’s actually two programs:
- Tableau Prep Builder creates the data flows for the transformation.
- Tableau Prep Conductor schedules and manages the data flows.
It is part of the Tableau Creator package as well, so it is included in the $70 per user per month cost.
What is Tableau Server and where is it based?
Tableau Server is a program that stores and serves previously created Tableau files. It organizes Tableau Desktop files. This can be useful if you work in an organization where many people use Tableau, either creating visualizations (“vizzes”) or using them.
It’s based on your own physical servers or it can be deployed on a public cloud platform such as AWS, Azure, or Google Cloud.
What is Tableau Online? What is the difference between Tableau Online and Tableau Server and how much does each one cost?
Tableau Online is akin to Tableau Server, except that files are stored on Tableau’s own servers. Therefore, it is a lot quicker to set up and eliminates the hardware cost.
You can choose to have either a Tableau Server or Tableau Online license as part of your Tableau Creator package, so it is included in the $70 per user per month cost. However, you can still access Tableau Online or Server with cheaper licenses.
Creating your first visualizations
What are the tabs that are located at the bottom of the Tableau window?
The left-hand most tab is the Data Source. In this tab you can:
- Load data from sources including spreadsheets and databases
- Create relationships or joins between data
- Assign data tabs and rename or hide fields
The other tabs are used to create vizzes, dashboards, and stories.
What are shelves used for?
The two shelves at the top of the Tableau window are the column and row shelves, which are the equivalent of the X- and Y-axis. The other shelves include the pages shelf, the filters shelf, and the marks shelf. Users can drag fields to all of them. There are six different types of marks: color, size, label, detail, tooltip, and shape.
What is “Show Me!”?
“Show Me!” is a button in the top-right of the Tableau window. When clicked, it reveals a list of around 20 types of vizzes.
If you highlight fields in your data sources, the list will only show the vizzes that are compatible with your selected fields. For example, you can’t create maps unless you have geographic data.
Clicking on any available viz in “Show Me!” will create the viz, putting the fields on the shelves and marks.
In other words, “Show Me!” allows you to kick-start the creation of vizzes.
How do you select multiple fields?
Click on a field then hold down Ctrl (or Command on the Mac) and select Additional Fields.
How do you change the colors used in a visualization?
- If all the marks are the same color, you need to include a field that shows which color to use. To add a color element to a viz, drag a field into the color mark.
- To change the colors used in a viz, go to the color scale on the right-hand side of the Tableau window, click on the arrow near the scale, and select Edit Colors. You can now change the Palette.
How do you add a filter to a visualization that the end-user can edit?
To add a filter to a visualization:
1. Drag a field to the Filter card
2. Select your initial values and click OK
To enable the end-user to edit this field click the arrow on the top-right of the Filter card and select Show Filter.
The filter will then be shown on the right-hand side.
What is the difference between a standard filter and a context filter?
Normally, all filters in Tableau are calculated independently, without any regard to other filters.
For example, suppose you have one filter showing different types of cars and another filter showing the Top 10 vehicles by car sales.
If you filter on a particular type of car, the results of the Top 10 filter will remain the same. It will not be recalculated based on the newly applied filter.
Context filters reduce the number of rows before any other type of filter is considered.
If you change the filter for the type of car to be a context filter, then the Top 10 filter will be calculated second, after the type of car filter. In other words, the Top 10 filter will be recalculated based on the results of the context filter.
In Tableau, what is a dashboard?
A dashboard is one or more vizzes shown on one canvas. The canvas is limited in size, so the vizzes adjust themselves to the size available. Additionally, the vizzes can interact with each other.
How do you predesign a dashboard?
To predesign a dashboard, drag horizontal and vertical objects into the canvas. This allows you to add vizzes into the objects that you have dragged in.
It may be advisable before you predesign your dashboard to:
1. Drag in a viz which already has a field in the filter card
2. Add a horizontal object in the right-hand side
3. Drag the filter into this new horizontal object
4. Pre-design the rest of the dashboard
What is the Device Designer?
Tableau dashboards can be viewed on different devices, but with each device’s unique resolution specifications, different amounts of vizzes will fit on the screen of each. The resolution for an iPhone is smaller than an iPad, which is smaller than a 30-inch monitor. So a one-size-fits-all approach for dashboards won’t be optimized for your particular device.
The Device Designer allows you to create an alternate dashboard for various devices. For an iPhone, you might have simplified vizzes and a smaller number of vizzes. For a large screen, you might have additional vizzes or more space allocated to the existing vizzes.
How can you use a highlight in one viz as a filter in a dashboard?
First, click on the filter symbol near the top-right hand side of the first viz. This helps create an interactive dashboard that is more useful to the end-user.
What are geographic roles for fields?
Certain fields in your data may have specific significance with respect to geography. Geographic fields can be numerical, such as latitude and longitude. Or they can be text-based, such as country, county, state, city, and zip code.
To assign a field a geographic role, change the field type from Text or Number to a type under the Geographic Role section.
What is a density map? How is it different from other types of maps?
A density map shows points on a map, based on the data. However, there may be several points on top of each other. In that case, a density map would allow the points to change color. This shows the increased density of the points.
Other types of maps show the data graphically as follows:
- They could show points of the same (or different) color, but perhaps with bubbles of different sizes.
- They could have areas (instead of points) such as states colored according to their size.
Organizing and simplifying data
Why would you want to build a hierarchy? How do you do this?
Hierarchies allow you to arrange fields that are connected into a logical order. For example, you could have a hierarchy of country-state/province-city. This would allow you to distinguish between cities with identical names, such as London, England, and London, Ontario. There can be as many levels in the hierarchy as you wish.
- To create a hierarchy, right-click on a field and select Hierarchy —> Create Hierarchy.
- To add fields into a hierarchy, either drag them in or right-click on them and select Hierarchy —> Add to Hierarchy.
How do hierarchies interact with filters?
Suppose you had a “Country – City” hierarchy set up.
If you filtered on the country Canada, any non-Canadian cities would now be unavailable to select in the filter. This means you could not accidentally filter on Canada and then expect London, England to be an option on the second filter.
What is a group?
You may have many unique values in a dimension. For example, in a field called “Vehicle Type,” the values may be “Green car 1”, “Red car 2” and “Yellow car 3.”
If there are too many distinct values, then that may make data analysis more difficult, since there would be a high number of rows.
However, if you group these values together into a new group called “Cars” and group other values into appropriate groups, then this can significantly reduce the number of rows in your analysis.
Grouping is a way of allocating unique values in a dimension into a higher level.
Advanced visualization techniques
What are reference lines?
Reference lines are lines superimposed on a chart. For example, you could calculate the average of the sales volume over a particular period. This can be shown:
- Over the entire chart
- Over each section (for example, per year)
- Over each cell
You can use the minimum, maximum, median, or total of a measure, or you can use a constant figure.
What are reference bands?
Reference bands are the same as reference lines, except they are filled in a transparent color. You can show the fill:
- From the bottom of the chart to the result of a calculation (for instance, to the total of a measure)
- From the result of a calculation to the top
- Between two calculations
What is the Summary Card, and how do you see it?
The Summary Card shows various statistics about your viz. By default, it shows the Sum, Average, Median, Min, and Max for the data in your view.
You can surface it by clicking to Worksheet —> Show Summary.
Customize what is shown by clicking on the drop-down arrow in the top right of the card, and adding or removing statistics from the card.
What is a parameter?
A parameter is a way for the user to enter a value so that value can be used in the viz. For example:
Maybe you want to hide all transactions below a certain value, but allow the user to change that value.
Or maybe you want to show the top 10 values in a dimension (based on the total of a measure such as sales), but allow users to change the “top 10” to become a top five or 20.
Adding a parameter is easy — in the Data tab on the left-hand side, click on the drop-down near the Search box and select Create Parameter.
How can you make a parameter dynamic so that it updates the available options based on any updated data?
This can be done in Tableau 2020 or later. To do so:
- Make sure the parameter has its Allowable Values to be driven from a List (instead of using All or a continuous Range of values).
- Instead of using the Fixed values, which create a list of values based on data available at the current time, change the list of values to be generated “When workbook opens.” Select the relevant field which contains this data.
- When the data in the field changes, the list of values shown in the parameter will be updated when the Tableau workbook is next opened.
What is a union?
A union creates a single table from two or more tables from the same data source, ideally using tables that have the same field structure. This will create a table that contains all the rows from the first table, and all the rows from the second table.
For example, you might be creating a union of January’s transaction data with February’s, or data from two separate departments.
What is a blend?
Blending is another way of combining data from multiple data sources. It can be useful when the fields needed to join tables change between vizzes.
Blending has generally been superseded by relationships from Tableau 2020.2 onwards.
What is the difference between a live connection and extracts?
Extracts are pre-queried data that has been saved so that it is optimized for Tableau aggregation. It is only up to date when the extract has been created or when it is subsequently updated.
Live connections query the data source (for example, from a database) when needed. As this is not optimized for Tableau aggregation, it can be slower and requires network activity when the live connection query takes place.
Tableau Online generally uses data extracts only. However, Tableau has been adding live connections for certain cloud databases.
I hope that you have enjoyed these interview questions. If any of the data visualization questions have left you stumped, then I hope that you will consider filling in the gap by joining me on my Tableau course.
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