Complex data questions are hard to answer with simple visuals. When questions have multiple components, a single graph may not be enough. For instance, imagine you have a table of data displaying average daily high temperatures by month that looks like this:
As you likely know from using Table Calculations in Tableau, they only compute against the marks displayed in a worksheet. Check out this webinar in you need a refresher.
That means when a filter is applied to the worksheet, a table calculation will update to reflect only the data present in the worksheet.
You may have noticed that under “Compute Using” in the Table Calculation dialogue box there is a section called “Specific Dimensions” where you would normally select a scope and direction. You generally only need to use Specific Dimensions when you have 3 or more dimensions in the view.
Take a graph like the following:
Let’s say you want to visually distinguish the 5 days with the lowest profit ratio. I’ll show you how I prefer to approach situations like this.
I shared an example with a class recently about how to use Table Calculations in Tableau and got a request to share this via a write-up. One of the most powerful things about Table Calculations in Tableau is the ability to set a scope and direction.
When calculating growth rates from one date period to another, it’s important to compare apples to apples. For instance, when building a graph in Tableau to compare quarterly sunscreen sales in Seattle, I probably wouldn’t want to compare Q3 Sales (July - September) to Q2 Sales (April - June) because there will be more sales in Q3. The product has a cyclical sales cycle. Instead, I would rather compare Q3 Sales of this year to Q3 Sales of last year to more accurately understand growth rates.