Power BI growth rate calculation YoY

Question

I'm having some difficulty getting a YoY change % for values in Power BI. The averages don't come out proper. I've come to understand this is an AVERAGE vs AVERAGEX issue in Power BI.

I need to create charts of year on year growth monthly. So Jan20 % change from Jan 19. I thought what was below was correct, but it is always throwing an issue for the month of February and a few other months. But some of the months are correct. My Measure is below.

Growth = 
IF(
    ISFILTERED('Oct5_5'[TRAFFIC_DTE]),
    ERROR("Check Time Filter."),
    VAR PrevMonth =
        CALCULATE(
            AVERAGE('Oct5_5'[VISITS_AMT]),
            DATEADD('Oct5_5'[TRAFFIC_DTE].[Date], -12, MONTH)
        )
    RETURN
        DIVIDE(
            AVERAGE('Oct5_5'[VISITS_AMT]) - PrevMonth,
            PrevMonth
        )
)

Snippet

Can someone please show me how to use the right Average? Thank you so much!

msta42a msta42a · Accepted Answer · 2020-10-09T20:53:03

Do You have all calendar days in your traffice_dte?

Probably not. This causes you to go back to a date that does not exist, which causes an error.

DATEADD function work ok if you use it on "calendar" tabel.

Requirement below: https://dax.guide/dateadd/

The Date table must always start on January 1 and end on December 31, including all the days in this range. If the report only references fiscal years, then the date table must include all the dates from the first to the last day of a fiscal year. For example, if the fiscal year 2008 starts on July 1, 2007, then the Date table must include all the days from July 1, 2007 to June 30, 2008. There needs to be a column with a DateTime or Date data type containing unique values. This column is usually called Date. Even though the Date column is often used to define relationships with other tables, this is not required. Still, the Date column must contain unique values and should be referenced by the Mark as Date Table feature. In case the column also contains a time part, no time should be used – for example, the time should always be 12:00 am. The Date table must be marked as a date table in the model, in case the relationship between the Date table and any other table is not based on the Date.

Power BI growth rate calculation YoY

1 Answers