Data Viz Done Right

August 29, 2017

Tableau Tip Tuesday: Using LODs to Compare a Month to the Historical Monthly Average

For this week's tip, I show you how to use a LOD expression to calculate the average for a month across all years and then compare each month in each year to that average. This is a very useful example if you want to see how a month compares to a historical average.


  1. Thank you for your sharing! It is very helpful!

    One quick question: if I only want the average for the year of 2014 and 2015 and draw a graph for data of these two years. How may I approach it?


    1. Inside of the LOD after the : you would do something like : IF Datepart('year',[Date])=2014 OR Datepart('year',[Date])=2015 THEN [Sales] ELSE 0 END }

    2. Thanks for sharing this. This is exactly what I was looking for, except now I also need the average of the last 2 years only (by month). I tried adding IF statement in LOD and it's not returning the correct result.

      { FIXED DATEPART('month',[Date]): AVG(

      { FIXED DATETRUNC('month', [Date]): SUM(IF Datepart('year',[Date])=2016 OR Datepart('year',[Date])=2017

      THEN [Number of Records] ELSE 0 END)})}