YTD Average of % on Time by Month and by Project

Hi. Hoping that someone much better at DAX than me can help with my issue.
I have a Fact table (TBL_Supplierdata) that holds data regarding suppliers and whether they deliver goods on time. We have 40 suppliers and each one delivers once a month, to supply one or more ‘Projects’. There are 4 ‘Projects’ which I have named Red, Blue, Green and Purple (changed due to sensitivities of data). The table has 4 columns - ‘Month/Year’ which is entered as first day of the month, ‘Project’, ‘Supplier Name’ and 'Reported Late (Y/N). Due to data sensitivity, Suppliers have been called A, B, C, D etc.
Example data below

Month / Year Project Supplier Delivered Late (Y/N)
01/01/2024 Red Supplier A N
01/01/2024 Red Supplier B N
01/01/2024 Blue Supplier C Y
01/01/2024 Blue Supplier D Y
01/01/2024 Green Supplier T Y
01/01/2024 Purple Supplier F Y

The table holds a similar set of data for 01/02/2024, 01/03/2024 etc… I need to work out the % of suppliers who delivered on time (so ‘N’ in Delivered Late column) for each Project by Month. I then need to calculate the YTD Average by Project.

The resultant table visualisation would look like the below

Month Project % Reported on Time - Month
01/01/2024 Red 50
01/01/2024 Blue 70
01/01/2024 Green 80
01/01/2024 Purple 65
01/02/2024 Red 60
01/02/2024 Blue 40

and then calculate YTD Average based on the value above. The example below shows the desired output (and shows two Projects ‘Red’ and ‘Blue’

Month/Year Project Montlh % on Time YTD Average
01/01/2024 Red 60 60
01/02/2024 Red 50 55
01/03/2024 Red 40 50
01/01/2024 Blue 80 80
01/02/2024 Blue 98 89
01/03/2024 Blue 76 85

With this I need to create two visualisations, both line charts with Month/Year (Jan 24, Feb 24 etc.) on the x-axis and YTD Average on Y axis with Project as the legend (or I could create individual measures and use ‘Project’ as a filter, if its easier and then add the four measures to the visual).
The second line chart visual is an overall for the business, so as per the above but not split by Project. Second upload shows what I need to achieve (but with only YTD months on x-axis).

I have done lots of reading around and tried lots of different things including AverageX with a ‘summary’ table inside but I’m not getting the correct results. I have also tried giving values to the ‘Y’ (0) and ‘N’ (100), in case that made it easier but didnt help me much. The more I think about it, the more confused I’m getting! IPBI file upload.
Thank you so much in advance, feel like I am going slightly mad. Please let me know if you need anymore information

Supplier Reporting.pbix (205.0 KB)


I see some potential problems. One set relates to your date table, another to the two tables you have connected to it, and the last to how one of your measures is calculated.

As for the date table, first, you need to make some adjustments to how you are using the date table in the data model. You should mark your date table as a date table. Although this is not strictly necessary your time-based calculations will be more reliable if you do. Then, establish a direct relationship between your date table and TBL_SupplierData. This ensures all date-related calculations are accurately filtered and aggregated. Finally, leverage the date table to replace the functionality provided by the Month Year Short Rank table. The Calendar Table can handle chronological sorting and indexing, eliminating the need for that redundant table.

Second, instead of using pre-aggregated summary tables like Month Project Split Summary, just incorporate that logic directly into DAX measures. For instance, convert the logic in the Month Project Split Summary table into measures that calculate on-time, late, and total deliveries directly.

Finally, your existing % on Time YTD measure uses TOTALYTD, which might not correctly capture the average of percentages through the year. Here’s an alternative measure that uses AVERAGEX to calculate the YTD average, ensuring that each month is correctly weighted and aggregated:

        VALUES('Calendar Table'[Month & Year])
        , [% on Time]
        ALL('Calendar Table'[Month & Year])
        , 'Calendar Table'[Month & Year] <= MAX('Calendar Table'[Month & Year])

This version recalculates the YTD average by taking into account all unique months up to the current month in your reports.


Hi HufferD.
Thank you so much for your reply. Worked like a treat, really appreciate your help. Think I had just started on the rights line when I gave up and decided to ask for help, in that I had started to build measures instead of a summary table. I had also marked the Calendar Table as the ‘Date’ table just after I uploaded the PBI file to the forum. I was ‘close’ but ‘so far’!. Thank you again.