Percentile over time

I have a set of data that includes a project, its completion date, and a value score assigned to that project. I’m trying to create a visual that will show the MoM P50 value of the score(looking back 12 months). So, for example, in July this would look back over the projects completed last August-July and get the P50 value of all of those scores and that would be the month’s data point. June’s data point would be the P50 of all the project scores from July-June. I’ve tried a number of different percentile and median functions but nothing seems to work as I’d expect it to. Any guidance on how to implement this? Thanks

Why doesn’t the group by level work? Where your group-by would be the month?

percentileDisc(expression, percentile, [group-by level])

Maybe my group-by is a problem and I could use assistance with what that would be. I was trying the “Date Completed”, but that probably isn’t right.

The fields I’m using in my visual are “Date Completed” and “Value Score” and can be seen below

So for median value I would do this below but I’m stuck on the unknown part. Do I need an ifelse on something?
percentileDisc({Value score}, 50, [])

Hmm, I don’t know if what you are trying to accomplish is possible.

Doing a partition by Date Completed would only look at that one day.

Now you’re trying to do it for all the dates of the past 12 months (for that date). So it would be different for each row. All in all to say that I don’t think a partition would work in this case.

I can mark this as a feature request as I don’t know how you would solve it currently.