Tableau: Calculate 14 Day Change in Covid Cases

Step 1:

Start with date on rows, and sum([Cases]) on Text

Step 2:

Create a lookup calculation to find the value from 14 days ago. Lookup(sum([Cases]),-14)

Step 3:

Calculate the difference by subtracting the two.

Sum([Cases]) – [14 Days Ago]

Step 4:

If you add a dimension like state, adjust the partitioning of the table calculation

Step 5:

Click the dropdown on your lookup and difference pills. Choose edit table calculation.

Step 6:

Uncheck any dimension where you want the lookup to be repeated. In this case, we want 14 days ago for each state. (unchecked state)