List.Average calculation problem

[doug_morris]

List.Average is not computed correctly in this code.

[
    Source = #table({"Value"}, {{null}, {1}}) & #table({"Value"}, {{2}}),
    Avg = List.Average(Source[Value])
]

It computes to 1 whereas it should be 1.5. Such incorrect List.Average calculation seems to occur anytime you are working with a non-buffered table built by combining tables. If you do an average on a column in the table like the code above or in a Table.Group, the average calculation erroneously includes nulls in the value count for the denominator. If you buffer the table or buffer the list before averaging, the error does not occur. I do not see this error with List.NonNullCount, List.Median, or List.StandardDeviation.

Has this been raised as a defect with the Power BI team? I've tested this behavior with multiple tables in both Power Query for Excel and Power BI and the defect shows up in all cases.

[Vijay_A_Verma]

This is a nice reporting. The issues (or bugs) can be reported to Power BI Dev team from here

https://community.fabric.microsoft.com/t5/Issues/idb-p/Issues

After searching there, I don't see any issue logged in this regard.

So, you will have to help out the community by logging an issue there. 

[doug_morris · Accepted solution]

Thank you, Vijay, for directing me to the right place to submit such issues. I have done that now and here's a link to the submission. Please fix this defect in List.Average - Microsoft Fabric Community