Try creating a calculated field, N, with the formula: SIZE()
Add N to your view (tooltip?) and on the pill, select Compute using > PATIENT_ID
Another option is to use an alternative format box plot without the Path trick. Remove PATIENT_ID from path and change the Mark type to shape > circle. You might want to change the color to make the marks semi-transparent.
Now you can see the individual points, which I think is helpful, especially for outlier detection. With the Path technique, you can't see if it's only one outlier pushing the bars to the max / min, or if there is a group, or if there is a long tail.
Thanks for the reply! I think we are getting closer!
I tried both of the above suggestions. It's great to know about SIZE(), however in this case, since we have more than one row per patient, size() gives me the number of records instead of the number of patients.
I also had arrived at creating the box plot without using the Path trick - you're right, it's so much more informative to be able to see individual data points. However, it still seems to think that I am partitioning by PATIENT_ID, even though I have removed it from the level of detail and the path.
I will keep trying things (perhaps experimenting with using size()) but if you have any more ideas, I would love to hear them!
If you could post an example twbx (packaged tableau workbook), even with 10 or 20 dummy records in Excel, it'll help. I'm sure whatever you need is possible in Tableau, but it'll probably require a table calculation, and table calcs are often specific to your view layout and data.