Dynamically Change Your Drop-Down Menus Based on a Selection

 

My colleague Jennifer Dawes, who just made a permanent transition from our HR department to Analytics (yay!), recently shared a public visualization focused on Gallup’s Strengths Finder.  If you are not familiar with Strengths Finder, it is an incredible way to determine the top strengths of your team members, which allows all of us to better understand how others on our team think, feel, and behave.  It’s an incredible tool and you can learn more by visiting their website.

Jennifer developed this visualization for work then anonymized it to share publicly.  In the actual visualization, it included about 100 people and showed the top five strengths of each person – 500 strengths total. Each strength was plotted as a circle by the type of strength as well as the ranking of that strength (top strength would be one, second strength would be two, etc.).  When you hover over a circle, it highlights the five total strengths for that person (five circles).

 

The intention of this tool was to allow managers and leaders as well as individuals to gain a better understanding of how their team members and colleagues “think, feel and behave”.  Jennifer decided to add some drop-down menus to allow users to dig into the details.  She set up a parameter to allow users to highlight sections based on Department, Manager, or by Individual Employee.  She then set up three additional parameters, one for each option.  The user would select the type of highlight in the first parameter then choose a value from the associated parameter.  To make it clear to the user, she noted which parameter menu was “active”.  Below is a GIF of what this looked like:

This may be a bit small, so here is a version zoomed into the parameters: 

After a bit of user testing, we learned that this was quite confusing.  She was showing these three parameters at all times, but only one of them was actually active.  It just wasn’t intuitive. This isn’t a jab at Jennifer in any way, we originally worked together to build this solution. 

 

In a meeting between Jennifer and me, she brought up this issue and we worked toward a solution.  We ultimately landed on a technique that would provide the first parameter to select how to highlight then a second drop-down to allow users to highlight by values specific to the first drop-down menu.  This parameter changed dynamically based on the first.  This means we eliminated the confusion of three additional drop-downs when only one was active and in addition, we cleaned up the view, trimming the number of drop-downs from four down to two.  Check out how it now works:

Again, this is a bit small, so here is a zoomed in version:

 

Okay, so how do we build this?  It’s actually quite simple and will utilize some of the new functionality released by Tableau in 2020.  To demonstrate this, I’ll be using data from gapminder.org looking at birth rate versus life expectancy.  But, rather than reinvent the wheel, I borrowed the work of someone else.  I want to give a big shout out to fellow Tableau Zen Master, Marc Reid who allowed me to use the base of his Gapminder viz that he used to demonstrate animations in Tableau.  If you haven’t seen this viz, it’s incredible and I recommend you check it out here: How has the world changed since 1962? (based on the work of the great Hans Rosling). Thank you, Marc, for allowing me to utilize your viz. 

 

Okay, let’s check out the data and then look at how the drop-down menus work.  First, please go to my Tableau Public viz.  We will focus on the sheet based on highlighting, not filtering.  Feel free to play with the controls before to gain a better understanding of the user interface.  As you can see, we are looking at birth rate (namely average number of children per woman) versus average life expectancy.  Each country is shown in the scatter plot as a circle and sized based on population.  The color represents region.  In my viz, however, only the South Asia region is highlighted and all others are gray. 

In this viz, we want to give the user the ability highlight by Region, Country, Life Expectancy Range, Children per Woman Range, and Population Range.  We could use five parameters (remember, they are single select) or we could use the five set controls to do this.  However, this could get quite confusing as one may interfere with another.  For example, let’s say you first highlighted the East Asia region then tried to highlight the United States.  We could control this using relevant values for set controls (available in 2020.3 – see #2 in my New Features blog post for more information) or we could force the user to go back and clear out previous selections.  But in general, it would be nice to not have to do either of those.  So let’s solve for that problem.

  

First, let’s create a high-level parameter.  It should be a string, list parameter – let’s call it “Highlight By”.  In the parameter, I included values for Region, Country, Life Expectancy Range, Children per Woman Range, and Population Range.  We then add this to our view. 

Now we need to build the secondary, dynamic drop-down to allow us to highlight by specific values within that list of values (for example, the South Asia region or the country of Canada).  To do this, let’s create a calculation to toggle the list of values:

 

Secondary Highlight/Filter Calculation

         CASE [Highlight By:]

    WHEN 'Region' THEN [Country Group]

    WHEN 'Country' THEN [Country]

    WHEN 'Life Expectancy Range' THEN [Life Expectancy Ranges]

    WHEN 'Children per Woman Range' THEN [Children per Women Ranges]

    WHEN 'Population Range' THEN [Population Ranges]

END

 

This calculation is pretty simple; it just says that when that particular value is selected in the parameter, use the corresponding dimension.  (Please note that for the three “range” dimensions, I manually created ranges – like bins – to group them).  Now if we added this calculation to a table, the values would change as we toggle the parameter:

 

Okay, now we need to allow the user to pick any of these different values to highlight on.  To do this, we are going to use Set Control.  For a quick overview on Set Control, check out #2 of my this blog post (note that this blog post focuses on relevant values within set controls, but provides a quick overview of set controls themselves).  So let’s create a set on this new calculation.  Right-click on the “Secondary Highlight/Filter Calculation” pill and choose Create à Set.  Name the set “Secondary Highlight/Filter Set” and for now, don’t add any values to the set (we will do that later).

  

Okay, we are almost to the finish line.  As you know, we want the user to be able to use the parameter then this set control to highlight different portions of the viz.  As we mentioned before, we are highlighting…or changing color based on the region.  Therefore, if we choose populations of over 1 billion, each country with a population over 1 billion will be shown in the color associated with its region.  So let’s create a calculation to place on color to only show the color when the value is in the set:

 

Color

           IF [Secondary Highlight/Filter Set] THEN [Region]

ELSE 'Other'

END

 

So if the value is in the set, then highlight it based on the region.  We will then place that onto the Color card.  Click the Color card and set the “Other” value to a very light gray.  You can leave the other colors as is.

 

From here, we simply need a method to add values to the set.  As mentioned, we will use set control.  In the Side Bar pane, find the “Secondary Highlight/Filter Set” pill and add it to the Detail card. Right-click on it and choose “Show Set”.  We can test it here, but let’s first bring everything onto a dashboard.  Add the “Dynamic Drop-Down – Highlight” sheet, show the “Highlight By” parameter and show the “Secondary Highlight/Filter Set”.

 

Okay, let’s give it a test run.  Look at the Set Control values and check a few to highlight the marks in the viz.  Now change the parameter to another value.  See how the set values have changed to correspond with the parameter selection?  You should have also noticed that the highlighting disappeared when you changed the parameter value…this is because those originally selected values don’t exist in the updated set.  Below is a GIF showing the functionality and simple user interface. 

 

Success!  We now have just two-drop down menus instead of five and the experience is much cleaner for the end user.  However, what if we want to filter the view instead of just highlight?  Well, as you probably guess by my car salesman pitch, “I’ve got just the thing for you!” 

 

Converting this over to a filter instead of highlight is very simple.  Just create a calculation called “Filter by Set” and make it equal to the set itself.  This will result in a True | False; either it’s in the set (TRUE) or its not (FALSE).  Now place that calculation on the filter shelf and set it to TRUE only.  Now when you choose items from the dynamic set, it will show them and filter everything else out.  You can check this out on the filter version of my corresponding example viz.

 

Well, that’s all I have for you.  Thanks so much for reading and if you ever have any questions or comments, please feel free to reach out at any time.

 

Kevin Flerlage, October 5, 2020

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