Think of { FIXED [A], [B] : XXXX } as "for each combination of A and B, calculate XXXX", and present that value.
If you don't include the [H19 - Term] into the expression, it will calculate the expression only for each student (independent of a term), and each term would show the same value for a student.
Thank you very much for the explanation/interpretation.
Rachel
Rachel,
Just to expand on Ewald's explanation:
You can think about the FIXED command telling Tableau to ignore the other grouping on your viz, and just calculate the values based on the grouping you are providing with the FIXED.
For example, let's say we want to know the number of students at each school. We can create a simple calculated field like:
And place it on our viz, with School Code on the Rows shelf, and we get:
Now let's create a calculated field, that does the same thing, but uses the FIXED command, like so:
When we place both measures side by side, we see they have the same result:
Now, let's "drill-down" in your viz, by adding the Term to our rows shelf, now we get different results for the two measures:
The "Count Of Students" measure uses the groupings that are shown on the Viz (on the Rows shelf) to determine it's calculations. The "Fixed Count Of Students", however, uses the FIXED command, and therefore, ignores the groupings on the Rows shelf that are any deeper than the groupings in the FIXED statement, and therefore still returns the same value as before. You can see this taken further if you add the "Course Id" to the Rows shelf, now the "Count Of Students" is telling you how many students are in each course within each term, at each school; and the "Fixed Count Of Students" simply stopped grouping at the School level, so that column is still just telling you how many students are at each school.
Hope that helps.
Kaz.
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