Sets are an extremely powerful feature of Tableau. They enable valuable analysis and can be used to answer incredibly complex questions.
Sets are special fields in Tableau that define a grouping of data by effectively identifying each underlying record of data as in or out of the set based on certain conditions you define.
Sets can be created in a couple of ways:
Select one or more marks in a view, and use the Create Set option on the tooltip controls. The set will contain every combination of dimension values that made up the selected marks:
Create a set from a single dimension by right-clicking on the Dimension field in the Data window and selecting Create Set… The resulting dialog box gives you the option of selecting individual dimension members (under the General tab) or setting specific conditions that define whether the data belongs to the set (under the Condition or Top tab):
