Introduction
Are you preparing to crush your Tableau interview? Or are you planning to sit for your Tableau Desktop Exam? If that, is you, then this article is for you?
Walking uncharted path can be intimidating for first timers, and that is why I have written this article to be your guiding star in your journey to becoming a Tableau developer.
These Tableau desktop interview questions have been curated by an expert with real experience in training and application of Tableau Desktop knowledge. These questions and answers will help you stand-out in your Tableau interview and by-extend get you ready for your Tableau desktop exam, gain immense skills that will help you establish your career and improve your earning potential.
These Tableau interview questions have been grouped into the following eight categories.
Introduction
Data connections
Organizing and simplifying data
Field and chart types
Calculations
Analytics
Mapping
Dashboards
Tableau interview questions (Introduction)
Quiz 1.0. What is Tableau?
Tableau is a leading data visualization software company focused on business intelligence (BI). Tableau has several products which together form the complete data analytics package. These products empower users,
Easily connect nearly to any data.
Combine, shape and clean data for analysis (prepare data).
Build interactive reports/visualizations.
Share reports/dashboards with users easily.
Quiz 2.0. What are the different Tableau products?
The Tableau product family consist of the following six products.
(i) Tableau Desktop - is the flagship tool for authoring dashboards. With Tableau Desktop, you can connect to a variety of data sources, combine and shape data for analysis, build interactive dashboards before you can publish reports (to Tableau Server or Tableau Online) for mass sharing.
One the key distinction of Tableau Desktop is its ability connect to lots of data sources as well as save workbooks locally in a computer.
(ii) Tableau Prep – is a self-service data preparation tool that empowers users combine, shape and clean data for analysis.
(iii) Tableau Students – Is a free Tableau Desktop and Tableau Prep license for all students at accredited academic institutions globally. To get your copy of Tableau license for students, all you need is to complete and submit a form to confirm your eligibility. You MUST be of 16 years and above to request this license.
(iv) Tableau public - is a free software which allows anyone connect to spreadsheet or file data and create interactive visualizations for the web.
One of the key distinctive features of the Tableau public is, it can only connect to limited data (file data) and it can only save workbooks on the Tableau public server.
(v) Tableau reader - this is a FREE desktop application that you can use to open and interact with workbooks build in Tableau Desktop.
(vi) Tableau server/online - is a platform to empower businesses explore data in a trusted environment. This platform allows organizations build, share, and collaborate around data analysis. Tableau online is hosted by Tableau while Tableau server is self-hosted.
Quiz 3.0. What are the advantages of using Tableau?
There are so many advantages to using Tableau Desktop with include,
Ease of use (Tableau uses drag and drop interface).
Speed (high performance).
Ability to connect to lots of data source (big data).
Ability to create beautiful interactive visualizations.
Easy way of publishing and sharing reports.
Ability to work with large volumes of data (big data).
Ability to support multiple data connections.
Thriving Tableau community and forum.
Quiz 4.0. What are the different Tableau file types you know?
When saving work, Tableau uses different file extensions to denote different file types such as workbooks, bookmarks, packaged data files, data extracts and data connection files. These different file types have been described below,
(i) Workbook (.twb) – Tableau workbooks files have .twb file extension. Such files when shared with users, require users to have the original data used to create the workbook to open them.
(ii) Workbook (.twbx) – Tableau packaged workbooks have .twbx file extension. A packaged workbook is a zipped file that contains the workbook along with the supporting file data and background images. Packaged workbooks are best for sharing with users who do not have access to the original data used to create the workbook. Packaged workbooks can be opened by both Tableau Desktop users as well as Tableau Reader users.
(iii) Tableau data extracts (.hyper or .tde) – When you extract data in Tableau to create a local copy that can be shared with others. Tableau uses the file extension .hyper or .tde to denote such data. Note, the file extension depends on the version of Tableau Desktop you’re using. For instance, when you extract data using Tableau 10.4 or any older versions, the Tableau data extract file will have .tde file extension while extracting data using Tableau 10.5 or new versions will create a data extract using .hyper file extension.
(iv) Bookmarks (.tbm) – Tableau bookmark files have a .tbm file extension. Bookmarks contain a single worksheet and are an easy way of sharing work.
(v) Tableau data source (.tds) – Tableau data source files have the .tds file extension. Data source files are shortcuts for instantly connecting to the original data. Data source files do not contain the actual data but rather the information necessary to connect the actual data as well as the modification made on top of the data.
(vi) Tableau packaged data source (.tdsx) – Tableau packaged data source contain the .tdsx file extension. The packaged data source is a zip file that contains the data source file (.tds) described above, as well as any local file data such as extract files, text files, excel files etc. Suitable when you need to share data with users who may not have access to the original data stored locally in your computer.
Tableau interview questions on data connections.
Quiz 1.0. What are the different ways you can combine data in Tableau?
There are four ways you can use to combine data in Tableau. They include, join data, union data, blend data and relate data.
(i) Join data.
Data joining is a method of combining tables related by common field. The results of combining data using joins is a virtual table that extends horizontally by adding columns of data.
(ii) Union data.
Data union is a method of appending values (rows) to a table. Note, to union data the tables must be of the same structure (same columns). Unioning data results to a virtual table with same columns but additional rows of data.
(iii) Blend data.
Data blending is another way of combining data – where data from secondary data source is displayed with values from primary source. Note, unlike data joining data blending keeps the data source separately but simply displays their information together.
(iv) Relate data.
Relating data is available for those using Tableau 2021.1 or later versions. Relationships describe how two or more tables are related based on a common field but does not merge the two tables together like in the case of joins. When you establish a relationship between tables, Tableau brings data from the related tables using the relationship to create a viz. (Check this article for more details about relationships in Tableau)
Quiz 2.0. What are the different join types in Tableau?
There are four join types that you can use in Tableau. They include, inner, left, right and full outer.
See the description below.
Quiz 3.0. In what ways can you connect to a data source in Tableau?
There are two ways you can establish a data connection in Tableau. You can either use a live connection to the underlying data source or extract data to Tableau in-memory.
Live connection – Is when there is a direct connection to the underlying data, enabling for a real-time or near real-time update of visualization when data changes.
Tableau data extract (.tde or .hyper) – is a snapshot of data optimized for aggregation. This snapshot is loaded in Tableau’s in-memory where it can be quickly queried for visualization.
Quiz 4.0. Explain what you understand by pivoting data in Tableau.
Pivoting data is the process of converting data in crosstab format (which can be difficult to work with) to columnar format. Pivoting data is suitable when dealing with multiple response questions (same data existing in separate fields) or when working with crosstab data.
Tableau interview questions on organizing and simplifying data.
Quiz 1.0. What are the different kinds of filters in Tableau?
Filters are used to limit the amount of data that goes into analysis.
There are six types of filters in Tableau, which are executed in the Tableau’s order of operations. The six filters are executed as in the order shown below.
Quiz 2.0. What do you understand by groups and sets in Tableau?
Groups and sets are similar in Tableau - both are used to combine members in a field.
In details...
Groups – are you used to combine related members in a field. Practically, groups are used for correcting data errors (by grouping related members together) or answering what-if-type of questions (what if we combine the ‘East’ and ‘West’ regions?).
Sets – Sets on the other hand are used to combine data based on some condition (by defining a subset of data based on some condition). Sets can be dynamic or fixed.
Fixed sets – Is one in which members of the set doesn’t change when the underlying data changes.
Dynamic set - is one in which members of the set change when the underlying data changes.
Quiz 3.0. What are hierarchical fields in Tableau?
Hierarchy is the arrangement where entities are presented at various levels. When you connect data in Tableau, you will note that Tableau automatically separate date fields into hierarchies – fields that can be used to break down your vizzes. Allowing users drill-down the view to see analysis at year level, quarter level, month level, day level etc.
By default, date fields are recognized as hierarchy fields in Tableau. Note, you can create custom hierarchies for example, using the field Region, State and City to create views which users can easily drill-down between the levels.
Quiz 4.0. What are the different ways you can sort data in Tableau?
Sorting data in the process of arranging data into meaningful form for proper data interpretation.
There are several ways you can sort data in Tableau.
(i) Sort from the toolbar
(ii) Sort by drag and drop (manual sorting)
(iii) Sort by specific fields in the viz
(iv) Sort from the axis
(v) Sort from the header
Tableau interview questions on field and chart types.
Quiz 1.0. What are the different data types in Tableau?
The following are Tableau data types.
Text (string) values
Date values
Date and time values
Numerical values
Boolean values
Geographical values (used in maps)
Quiz 2.0. What are measures and dimensions in Tableau?
Dimensions are found above the grey line on the Tableau data pane area. Dimensions contains qualitative values (such as names, dates, or geographical data). When added to the view dimensions reveal the details of your data.
Measures are found below the grey line on the Tableau data pane area. Measures contain numeric or quantitative values that you can measure. When you drag a measure to the view Tableau applies an aggregation by default.
Quiz 3.0. Explain the difference between continuous and discrete fields in Tableau.
Discrete fields mean individually separate. And in Tableau, you can distinguish discrete fields by the fact that they are blue in color – when dragged to the view, discrete fields add headers.
Continuous fields mean forming without interruption. In Tableau you can distinguish continuous fields using green color. Also, when dragged to the view continuous fields add axes.
Quiz 4.0. Mention different chart types you can build in Tableau?
Charts and graphs are the building blocks of data visualization. In Tableau, you can create hundreds of different charts and graphs to tell different data stories. Some of the charts you can create are shared below.
Tableau interview questions on calculations.
Quiz 1.0. What is a calculated field and how do we create one in Tableau?
Calculated fields allow you to create a new data from data that already exists in the data source. When you create a calculated field, you are essentially creating a new field (or column) in your data source.
To create a calculated field in Tableau.
Right click anywhere on the dimension or measure area.
Go to Create >> Calculated Field…
Alternatively.
Go to the Analysis menu.
Then select, Create Calculated Field….
On the calculated field editor, enter your computation.
Quiz 2.0. What will the following function return?
TRIM (SPLIT (“Bernard /Kilonzo”, “/”,1))
This function will return the string “Bernard”.
The SPLIT function will split the first part of the string “Bernard /Kilonzo” using delimiter “/” returning “Bernard “, before trimming the trailing space to return “Bernard”.
Quiz 3.0. What is Level of Detail (LOD) Expression?
Level of Detail (LOD) expressions allow you to compute values at the data source level and at the visualization level. LOD expressions give you more control on the level of granularity you want to compute. There are three types of LODs, INCLUDE, FIXED and EXCLUDE.
INCLUDE level of detail expression is used to compute a value using the specified dimension(s) in addition to whatever dimensions are in the view.
FIXED level of detail expression is used to compute a value using the specified dimension(s), without reference to the dimensions in the view.
EXCLUDE level of detail expression is used prevent the calculation from using one or more of the dimensions in the view.
LOD expression syntax
{[FIXED|INCLUDE|EXCLUDE] <dimension declaration> : <aggregate expression>}
Quiz 4.0. Explain the Tableau rank function.
Tableau rank function is used to compute the ranking for each value in a partition. There are five different types of ranks namely, RANK, RANK_DENSE, RANK_MODIFIED, RANK_PERCENTILE and RANK_UNIQUE.
RANK – This function returns the standard competitive rank for the current row in a partition. Identical values are assigned same rank. E.g., The set of values (2,5,5,8) would be ranked (4,2,2,1).
RANK_DENSE – This function returns the dense rank for the current row in a partition. Identical values are assigned same rank, but no gaps are inserted into the number sequence. E.g., The set of values (2,5,5,8) would be ranked (3,2,2,1).
RANK_UNIQUE - This function returns a unique rank for the current row in a partition. Identical values are assigned different ranks. E.g., The set of values (2,5,5,8) would be ranked (4,3,2,1).
RANK_MODIFIED – This function returns modified competitive rank for the current row in a partition. Identical values are assigned same rank. E.g., The set of values (2,5,5,8) would be ranked (4,3,3,1).
RANK_PERCENTILE – This function returns percentile rank for the current row in a partition. E.g., The set of values (2,5,5,8) would be ranked (0.00,0.67,0.67,1.00).
Tableau interview questions on analytics.
Quiz 1.0. What is the difference between reference lines and bands?
Both reference lines and bands can be added from the analytics pane.
When added to the view.
Reference line adds a constant or a computed value on the axis. While
Reference band shades an area behind the marks in the view either between two constant values or computed values on the axis.
Quiz 2.0. Mention/explain two charts which use reference lines to create.
Bullet chart and spine chart use reference lines to create.
Bullet chart – are variations of bar charts developed as a replacement of dashboard gauges and meters. Bullet chart is used to show progress towards a certain goal.
Spine chart – is a visualization that shows at a glance how one area compares with others across a range of indicators. With summary statistics of each measure such as the average aligned to form one central line or spine on the chart.
Quiz 3.0. Explain clustering in Tableau.
Cluster analysis partitions marks in the view into clusters, where marks within each cluster are more similar to one another than they are to marks in other clusters.
Tableau uses the K-means algorithm for clustering, where for a given number of clusters K, the algorithm partitions the data into K clusters. Each cluster has a center that is the mean value of all points in that cluster. K-means locates centers through an iterative procedure that minimizes the distances between each individual point in a cluster and the cluster center.
Quiz 4.0. Explain forecasting in Tableau.
Forecasting in Tableau uses a technique known as exponential smoothing. This is where forecast algorithms try to find a regular pattern in the measures that could be continued into the future.
Note, you can add forecast in a view that contains a date field and at least one measure. However, in the absence of a date field, you can create forecast to a view that contains a dimension with integer values in addition to at least one measure.
Tableau interview questions on mapping.
Quiz 1.0. When maps cannot be displayed in Tableau, how can you fix them?
There are several reasons why your Tableau maps are not displaying. The reason could be.
You have assigned the wrong geographical role.
You are using the wrong location.
You can fix this by,
Assigning the correct geographical role.
Editing location to assign the correct location.
Quiz 2.0. Explain map options used to customize how people interact with your maps.
Tableau map options allow you to customize how users interact with your maps. Some of the customizations you can make under map options include.
Show map search – used to search for locations within the map.
Allow pan and zoom – used to move maps and zoom in/out of maps.
Show map scale – used to display scale on maps as well as change scale units.
Show view toolbar – used to make visible the map toolbar which contains several map options such as pan and zoom and different selection types.
Quiz 3.0. Explain custom territories on Tableau maps.
Custom territories are formed by grouping existing locations together to create new locations or regions that can be used in the context of your analysis.
In Tableau there are several ways to create custom territories.
By selecting and grouping locations on the map.
By creating territory from a geographic field.
By geocoding a territory field using another geographic field.
Quiz 4.0. Explain the Tableau mapping workspace.
The Tableau mapping workspace contains of elements and objects required to create maps. The Tableau mapping workspace consist of.
The data pane – which contains geographic fields, latitude, and longitude fields.
The marks card – we drag geographic fields into the detail shelf to create maps.
The map menu – which contains different mapping options.
The view tool bar - which contains tools for customizing the view.
The visualization area – this is the area where the map appears.
Tableau interview questions on dashboards.
Quiz 1.0. Explain the Tableau dashboard design flow.
The process of designing a Tableau dashboard is as follows.
Connect data through different connectors available in Tableau Desktop.
Combine different data sets using different options available in Tableau, where need be shaping the data.
Create visualizations i.e., charts and graphs to answer various project objectives.
Create multiple views (different worksheets) to ensure all project objectives are exhausted.
Combine different views (worksheets) into the dashboard interface to create your dashboard(s) or report(s).
Hide all worksheets to remain with only the dashboard(s).
Publish your dashboard/report for mass sharing.
Quiz 2.0. How can you embed a webpage on a dashboard?
Sometimes you can embed a webpage on a dashboard (open URL actions inside your dashboard).
To do that,
Create a view to be used in triggering the URL actions.
On the dashboard interface add the view and a webpage object.
Add a URL action - set the URL action to target a web page object)
Quiz 3.0. Explain the different ways of sharing Tableau dashboards.
There are several ways of sharing Tableau dashboards which include.
Publishing dashboards on the Tableau Online or Tableau Server for governed sharing of insights.
Publishing dashboards on the Tableau Public for public sharing of insights, either through a link or embedding in different platforms.
Sharing as a .twbx file (Tableau packaged workbook) for Tableau Reader or Tableau Desktop users.
Sharing as a .twb file (Tableau workbook) for Tableau Desktop users with the original data used to create the dashboard.
Sharing as a pdf, ppt or image.
Quiz 4.0. What are the different ways of optimizing the performance of Tableau dashboards?
There are several techniques you can apply to speed your Tableau dashboards. Some the actions you can take include.
Reducing the marks (data points) in the view.
Limiting the number of filters.
Reducing the number of nested calculations.
Reducing the number of worksheets in a dashboard (dashboard scope).
Using Tableau data extracts to improve the performance of slow databases.
Minimizing joined tables.
Using Boolean or numeric calculations instead of string calculations.
Using performance recording to track actions taking longtime to run and find ways to improve them.
Conclusion
In this article, we have shared the most frequently asked Tableau interview questions, some which might be basic while others technical. The Tableau interview questions might change whenever Tableau is updated with new features and therefore, we promise to keep updating this article with the freshest content you can get on Tableau interview questions and answers.
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Thank you for reading.
--Bernard
