Dimensions vs measures (blue & green pills)

Every field in Tableau has two traits. First, its role: a dimension answers "by what" (by city, by product), while a measure answers "how much" (how many rupiah, how many units). Second, its colour once it becomes a pill: blue = discrete, green = continuous. Once these two click, almost everything Tableau does makes sense. Every step in this module is the same in Tableau Public and Tableau Desktop.

12345 Zoom

Click a number on the picture or in this list to highlight that area.

1. 1Dimensions Fields above the thin line (e.g. Channel, Product, Region) group your data; their icons are blue.
2. 2Measures Fields below the line (Cost, Quantity, Revenue) hold numbers you can add up; their icons are green. OrderID lands here too because it holds numbers.
3. 3Headers from a blue pill The blue (discrete) Region pill on the Rows shelf creates these headers: one row for each city.
4. 4Axis from a green pill The green (continuous) SUM(Revenue) pill on the Columns shelf creates this number axis (0M to 800M); you read the bar lengths off it.
5. 5Aggregation Pill menu → Measure (Sum) switches Sum to Average, Count and more.

Step by step

1. 1

   Step 1: Open a new sheet with the New Worksheet icon in the tab strip at the bottom. In the Data pane, look at the Sales table: fields above the thin grey line are dimensions (number 1: Channel, Date, Product, Region and more), while fields below it are measures (number 2: Cost, Quantity, Revenue).

   Tip: Italic fields such as Measure Names, Sales (Count) and Measure Values are generated by Tableau. Leave them alone for now.

   Watch out: OrderID sits below the line because it holds numbers, even though order numbers are not meant to be added up. This course never adds up OrderID, so leave it there. In your own data, you can move a number field like this with right-click → Convert to Dimension.

2. 2

   Step 2: Drag Region to the Rows shelf, then drag Revenue to the Columns shelf. Region becomes a blue pill and creates headers, one row per city (number 3). Revenue becomes a green pill labelled SUM(Revenue) and creates a number axis with bars (number 4).

   Tip: Tableau aggregates measures straight away, which is why it says SUM. One bar = the total Revenue of all orders in that city.

   Watch out: Pill colour does not mean dimension or measure. Blue means discrete (separate values → headers) and green means continuous (a range of numbers → an axis). Dimensions are usually blue and measures green, but a date can become either a blue or a green pill.

3. 3

   Step 3: Click the small arrow on the right of the SUM(Revenue) pill (or right-click the pill) → Measure (Sum) (number 5) → Average. The pill changes to AVG(Revenue), and the bars now show the average Revenue per order row. Switch back to Sum from the same menu.

   Tip: The same menu has Discrete and Continuous. Try clicking Discrete: the pill turns blue and the axis becomes number headers. Click Continuous to go back, or press Ctrl+Z (Cmd+Z on a Mac).