While revising for the Tableau Certified Data Analyst Exam, I thought it would be a good idea to do a series of Tableau Tutorials to consolidate my understanding for exploring and analysing data concepts. In this blog, I will be guiding you through what FIXED LODs (Level of Detail Expressions) are through a basic example, and a use case example from Bethany Lyons’ article: Top 15 LOD Expressions.

### Fundamentals

FIXED LODs calculate aggregated values for stated dimensions **independent** of other dimensions in the view, and are expressed in braces. To demonstrate, let’s decipher the following syntax using the Sample – Superstore dataset.

As a reference, we will use the table below to show the value of the expression above.

We can clearly see there is no difference when dragging both measures [Profit] and [Profit per Category]. However, if we drag and drop another dimension (e.g. [Sub-Category]) onto the view, we will obtain a clearer understanding of what the FIXED LOD is illustrating.

In the table above, we can notice that the profits for each sub-category are different but the FIXED LOD expression states the same value for each sub-category. Hence, FIXED LODs are **independent** and do not refer to any other dimensions except for the specified dimension. Further, I added a totals row for each category for confirmation.

### Use Case Example

This example will be covering the *Customer Order Frequency* from Bethany Lyon’s article using the Sample – Superstore dataset. Before diving into the calculations, let’s first take a look at the details by dragging and dropping [Customer Name] (preferably [Customer ID] if available) and a count distinct of [Order ID].

We want to provide a visualisation which returns the number of customers that have made 1, 2, 3, … , N orders as highlighted in the data labels above. To achieve this, we can use the following LOD.

This calculated field is a measure. To make this a label in our visualisation, we will convert it to a dimension. Drag and drop this dimension to the column shelf and an aggregated count distinct of [Customer Name] to the row shelf, and voila! We obtain a visual which illustrates the distribution of customer order frequency below.

We have now identified that 12 customers have made 1 purchase, 36 customers have made 2 purchases, etc.

If you have made it this far then I hope you have achieved a clearer understanding in FIXED LODs. Thank you for reading my first Tableau tutorial!