Calculated average of the last three months

[Anonymous]

Hi Power BI Community! 

Count of parts last three months

This measure: DOA rate (monthly) = var result =(DIVIDE('Parts per Month'[DoAs]; [Count of Parts]))+0

return if(result; result; IF(MAX(Dates[Date2])>DATE(2019;9;30);0; BLANK())) gives me the right per cent per month.

For example August= (1 DoA / 72 parts) * 100 = 1,39 % 

Now I have problems to calculated the average of the three month in per cent. 
For example last three months total 13,13 % / 3 months = 4,37 % 
How is this possible? 
I have a measure that calculats (all DoAs of the last three months (22 DoAs) / all Parts of the last month (421 parts))*100 
= 5,22 % 
Why is there a 0,85 % differenz?

Thank you for your time

[Anonymous · Accepted solution]

Hi @Anonymous 

I think this may be a mathematical problem.

(A1/A2+B1/B2+C1/C2)/3≠(A1+B1+C1)/(A2+B2+C2)

If I haven't explained clearly, substitute the formula into the number.

(1/2+1/4+1/4)/3=0.33 ≠ (1+1+1)/(2+4+4)=0.3

Best Regards,
Stephen Tao

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[amitchandak]

@Anonymous , try like with a date table

Rolling 3 = CALCULATE(sum(Sales[Sales Amount]),DATESINPERIOD('Date'[Date],ENDOFMONTH(Sales[Sales Date]),-3,MONTH))/3
Rolling 3 = CALCULATE(sum(Sales[Sales Amount]),DATESINPERIOD('Date'[Date],max(Sales[Sales Date]),-3,MONTH))/3

Rolling 3 till last month = CALCULATE(sum(Sales[Sales Amount]),DATESINPERIOD('Date'[Date],ENDOFMONTH(dateadd(Sales[Sales Date],-1,month)),-3,MONTH))/3

Rolling 3 = CALCULATE(Average(Sales[Sales Amount]),DATESINPERIOD('Date'[Date],ENDOFMONTH(Sales[Sales Date]),-3,MONTH))/3
Rolling 3 = CALCULATE(Average(Sales[Sales Amount]),DATESINPERIOD('Date'[Date],max(Sales[Sales Date]),-3,MONTH))/3

To get the best of the time intelligence function. Make sure you have a date calendar and it has been marked as the date in model view. Also, join it with the date column of your fact/s. Refer :
https://radacad.com/creating-calendar-table-in-power-bi-using-dax-functions
https://www.archerpoint.com/blog/Posts/creating-date-table-power-bi
https://www.sqlbi.com/articles/creating-a-simple-date-table-in-dax/

See if my webinar on Time Intelligence can help: https://community.powerbi.com/t5/Webinars-and-Video-Gallery/PowerBI-Time-Intelligence-Calendar-WTD-YTD-LYTD-Week-Over-Week/m-p/1051626#M184


Appreciate your Kudos.