Tableau Your Data!, 2nd Edition

Chapter 4 Creating Calculations to Enhance Data

Each new paradigm gives us the opportunity to “see” phenomena that were before as invisible to us as the colors of the sunset to the fog.

—Benjamin and Rosamund Zander¹

Tableau provides different methods for making calculations to enhance your data through the creation of new fields that don’t exist in your data source. You can also turn single-purpose dashboards and views into multi-purpose analysis environments though the use of parameter controls. Parameters are formula variables that can be used to provide filter-like controls that allow users to change the measures and dimensions used in a dashboard or worksheet. Starting with Tableau V9.0, an entirely new class of functions was added that eases control over the granularity of the data expressed in your views. Level of detail (LOD) expressions lower the technical bar for achieving effects that formerly required advanced SQL-scripting skills.

In this chapter, you will learn how to use Calculated Fields and Table Calculations to derive facts and dimensions that don’t exist in your source data. Tableau’s formula editing window will be explained as well as the Quick Table Calculation menu and how to modify the calculation defaults to address your specific needs.

You will learn about parameter controls—basic and advanced—so that you can make views that address different needs using the same basic visual design. Level of detail (LOD) expressions are covered at the end of the ...