Year-over-year comparison in Tableau - Cell-by-Cell Formula Trace

Sample Data

Sales data for two years, 2022 and 2023

Cell	Value
A1	Year
B1	Sales
A2	2022
B2	1000
A3	2023
B3	1200

Formula Trace

SUM([Sales]) - LOOKUP(SUM([Sales]), -1)

Step 1: SUM([Sales]) for current year (2023)

Step 2: LOOKUP(SUM([Sales]), -1) for previous year (2022)

Step 3: 1200 - 1000

Cell Reference Map

   A      B
1 Year   Sales
2 2022   1000
3 2023   1200

Formula references Sales in B2 and B3 for calculation.

The formula uses sales values from years 2022 and 2023 to calculate the year-over-year difference.

Result

   A      B       C
1 Year   Sales   YoY Change
2 2022   1000    
3 2023   1200    200

The YoY Change column shows the difference in sales between 2023 and 2022, which is 200.

Sheet Trace Quiz - 3 Questions

What does the LOOKUP function with offset -1 do in this formula?

A Gets the sales value from the previous year

B Gets the sales value from the next year

C Calculates the total sales for all years

D Returns zero

Key Result

SUM([Measure]) - LOOKUP(SUM([Measure]), -1) calculates year-over-year difference