Need Help on Autocorrelation Calculation

[Irwan]

Hello Power BI expert,

I need an advice on how to do autocorrelation calculation in Power BI.

for now i am trying to replicate the result from excel tutorial.

I read there are two ways of calculation autocorrelation:

1. Using OFFSET and DEVSQ

2. Using VAR.P

Here is the website link that i currently work on to replicate the result How to Calculate Autocorrelation in Excel - Sheetaki

Is it possible to re-create what the excel did in Power BI? I tried to make it myself but the result is different.

Thank you and really appreciate for the help.

[lbendlin]

Most likelky not.  Power BI has no memory and no concept of self-referencing without becoming all upset about circular references.

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[Irwan]

Hello @lbendlin 

here is the sample data. Basically that is a data came from the website that i mentioned (I am trying to recreate the result before applying it into real data).

Jan	56
Feb	58
Mar	69
Apr	50
May	66
Jun	68
Jul	78
Aug	73
Sept	88
Oct	90

 Here is the result that I wish to get in Power BI

However, if Power BI has no memory or concept of self-referencing, then it is impossible doing autocorrelation in Power BI?

Thank you and really appreciate for the help.

[lbendlin · Accepted solution]

Here you go

[Irwan]

Hello @lbendlin 

that DAX is superb, thank you.

I dont know if there is a sumx offset at line 6 (maybe) as a "bridge" before sumx the whole result as in Line 8 (thought it can be done directly by using earlier indexing).

I need to work again on my DAX understanding as a beginner.

Again, thank you and really appreciate for the help.

[lbendlin]

As always you can approach the issue with different DAX functions but you will want to unlearn EARLIER and embrace the window functions. Makes the shifted reference so much easier.

[Irwan]

hello @lbendlin 

sorry in advance, i got another question, is it possible to put the measure (the correlation result) into a new column?

Thank you and appreciate for the help.

[lbendlin]

You cannot create columns from measures. You would need to modify the code to create a calculated column instead

[Irwan]

Hello @lbendlin 

alright then, thank you again for the help and support.

[lbendlin]

Ah, that's actually simple - basically a special case for a Pearson correlation within the column.  Let me play with that a bit.