How to Make Dynamic Tooltips in Tableau

This prevented me from making a generic tooltip that said something like “[Year of Census] Population” because if the city was not in the top 100, this descriptive text would be followed by a null value / blank space:

In the screenshot, you can also see the second issue. If there is not data for Tableau to compute the census over census change, the “Census over Census Change” label is also followed by a null value / blank space. This is a potentially confusing user experience that I wanted to avoid.

The trick to creating dynamic tooltips is to create a calculated field that provides logic for what descriptive text to display for each mark. In my first case, if a city did not have a population measure because it wasn’t in the top 100, I would prefer my end users see “(Not in Top 100 Cities)” instead of the standard text for the other marks followed by a null value. The formula for this calculated field is:

IF ISNULL(SUM([Population])) THEN “(Not in Top 100 Cities)”
ELSE STR(MIN([Census]))+” Population”
END

This calculation looks at the population measure for each mark. If it is null, it displays “(Not in Top 100 Cities)”; otherwise it strings together the year of the census and the word “Population”.

This approach also works with table calculations. Here’s how I created a dynamic tooltip for the census over census change. Note that this descriptive text for the tooltip has three outcomes: (1) the first year of the census (2) census over census change is not available (as is the case when there aren’t values for Tableau to do the math and (3) the original standard “Census over Census Change”.

IF SUM([Census]) = 1790 THEN “First Year of US Census”
ELSEIF ISNULL((ZN(SUM([Population])) – LOOKUP(ZN(SUM([Population])), -1)) / ABS(LOOKUP(ZN(SUM([Population])), -1))) THEN “Census over Census Change N/A”
ELSE “Census over Census Change”
END

After creating these calculated fields to dynamically compute the descriptive text that will be displayed in the tooltip, I simply replaced my hard-coded text in the tooltip with these fields:

And now when I hover over a city that was not in the top 100 at the time of the census and/or a city where the data were not available to compute the census over census change, the end user sees a description that makes much more sense:

This is just one of countless examples, but the main point of the article is that you can leverage calculated fields with strings, the ISNULL function, and/or table calculations (plus more we didn’t cover) to improve the user experience with your tooltips!

Thanks for reading,
– Ryan