Introduction to calculations

Calculations in Tableau

Agata Bak-Geerinck

Senior Data Analyst, Telenet

Why do calculations?

Calculations allow you to create new data from data that already exists in your data source and perform computations on your data

Typical use-cases:

Measure missing in original dataset:
- e.g. Sales and Costs but no Profit measure
Transforming existing data:
- e.g extracting First name from First and Last name
Categorizing the data:
- e.g. grouping Age into "Kids", "Teens", "Adults", based on age thresholds
...

There are four main types of calculations:

Basic calculations:

Advanced calculations:

A snapshot of a spreadhseet

Row-level calculations
- Performed on each individual row
- e.g. End Date-Start Date

A table with start and end date and a calculation of a difference between a start and an end date

Aggregate calculations e.g. SUM(), AVG()
- Performed on set of records defined by dimensions in the view
- e.g Sum of Profit = SUM(Sales)- SUM(Cost)
- Recalculated per dimension in the view

A table presenting Sum of Profit per Region

Do NOT mix up row-level and aggregate calculations:
- Use only row-level or aggregation calculation

Example of erroneous calculation involving mathematical operations on incompatible data types

Watch out for syntax errors:
- Missing syntax elements, e.g. ELSEIF or END in an IF() statement
- Missing an identifier, operator, comma, or parenthesis
- Using incorrect bracket type {}, [], ()

Tableau validity check does NOT eliminate all errors!

Typical logical / mathematical errors:

Final analytical responsibility lies with you!

Visual representing a smart watch and various types of activities which can be tracked, such as sleep, heart rate and exercise

Calculations in Tableau