Practical Tableau

Chapter 7. Discrete Versus Continuous

The second big way Tableau classifies each field you are using is as discrete or continuous. This classification has an impact on what types of visualizations you can create as well as how they will look, so having a good grasp on what this distinction means is core to your understanding of how Tableau looks at your data.

It is easy to know if a field is being used as discrete or continuous based on its color. Blue indicates that a field is discrete, while green indicates that a field is continuous. If your first guess was that these colors represented whether a field was a dimension or measure, you are not alone. The thought that blue represents dimensions and green represents measures is the most common myth in Tableau. It’s easy to understand why because, by default, dimensions are categorized as discrete variables, and thus have a small blue icon in front of them in the Dimensions area of the Data pane. Measures are categorized as continuous variables, so they are prefaced with a green icon in the Measures area of the Data pane.

I assure you that the color-coding identifies discrete versus continuous fields and not dimensions versus measures. Measures can actually be used as discrete fields or continuous fields, and the same is true for some dimensions, such as dates.

So what does this mean for your visualizations? I will illustrate using two rules of thumb I have when considering if a field should be used as discrete or continuous: