Tableau not showing all data in box and whisker plot

Question

I am trying to create a box and whisker plot in tableau. It is not using all the data points to make its calculations, but seems to be first removing duplicates. Two rows in my backing CSV have the value 93, for example, but only one is making it through to actually generate the plots. This means my means are incorrect. If I view data I see that there are no duplicates, but if I view underlying data all the values appear as they should.

I can't figure out why this is, and I'm not able to make the calculation consider all of my data. Through googling I've found nothing similar to my problem. Does anyone have any idea why this is? I haven't selected remove duplicate data or anything of that sort, and I can't find anything helpful. It is extremely unsettling that tableau would be removing duplicate values without notifying me in any way or giving me the option to undo it.

Answer 1

Well after an hour and a half of cursing Tableau's name I figured it out. The problem was that Tableau doesn't make it obvious how to do a simple plot of points. I had selected "Dimension" for my row data type, as otherwise it was only giving me an aggregate value like sum or average--not very useful for a box plot. To get it to plot actual points, including duplicates, you have to select the Analysis menu item and deselect "Aggregate Measures".

This is confusing, as it appears to mean that it is all or nothing with your aggregate functions, and that you're deciding at the worksheet level rather than the data series level if you're going to be using aggregates.

Answer 2

There is a middle way between plotting every data point (i.e. deselecting aggregate measures) and plotting a single aggregate point. Put any combination of discrete (blue) fields in the visualization to group data points by those dimensions. So for example, if you put State on the level of detail shelf, you'll get one data point summarizing each state instead of one for each individual sale. This lets you control the level of aggregation to any degree desired.