Tableau Prep: Up & Running

Chapter 22. Creating Additional Data

The challenge with data preparation is often in cleaning and removing columns or rows of data, but doing so isn’t always necessary. When preparing data sets for analysis, you’ll often need to create additional data through certain techniques. This chapter will go through situations when you might or might not need to create data and then will cover the various data creation techniques in Prep.

When Not to Create Data

The aim of the data preparation process is to reduce the level of manipulation required during the data analysis. Therefore, anything you can do during data prep to simplify the “data work” of analysis is worthwhile. For example, any column or row that is not in the data set, but should be for your analysis, needs to be created. There are multiple techniques to do this, but first let’s explore where you shouldn’t be creating extra columns or rows.

Dynamic Calculations in Desktop

Tableau Desktop is designed to allow you to conduct analysis at the speed of thought—that is, to deliver answers as quickly as you can think of the questions. Part of this design are three types of calculations that factor in the data fields within your analysis as you build it onscreen:

Calculated Fields

Tableau Desktop calculates the measures used within a view based on the dimensions that are also present in the view. If you create a calculation for total sales, sum(Sales), Desktop will return the total sales of the entire data set if there are no ...