I know (and love) that I can switch between a Calendar and Fiscal view of my data at the YEAR level.
But I think it is flawed. Really, seriously flawed. Fiscal reporting in Tableau is simply inaccurate and unreliable.
Whilst Tableau does allow me to choose the calendar month on which to start my fiscal year,
fiscal years do not always end neatly on the start and end dates of a calendar month. And nor do fiscal months, fiscal quarters nor fiscal halves.
For example in my organisation, our fiscal year nominally starts in April and ends in March.
But this does not necessarily mean that it starts on the 1st April and ends on the 31st March.
Generally, fiscal periods end a fixed day of the week. In our company fiscal periods always end on a Friday.
This year, the final quarter ended on the 29th March, a Friday.
All transactions that occurred on the 30th and 31st March, whilst still in calendar March, were actually in Fiscal April.
What this means is that when I report financial transactions for fiscal periods of Quarters and Months, there is often (almost always) some discrepancy between what Tableau is reporting and what management accounts say.
The impact from month to month, might not be that serious ... but when it comes to the Quarterly, Half Year and End of Year results ... the results are simply not accurate, unreliable and hence unusable for formal management and financial account reporting.
What this means is that I cannot use Tableau for reporting financial data. Its simply flawed.
There are a couple work-arounds;
1) In the raw data, before it gets touched by Tableau, fiscal periods (months, quarters, halves and years) need to be defined as their own discrete dimensions. This is how I have solved this. The calculations are done in the data warehouse ... which sucks because it means I am reliant in IT.
2) Writing some code in Tableau, that looks up a fiscal periods in hard coded table of dates.
3) Re-date transactions so that they fall into the correct period. (yeah, right. good luck with that one).
Ideally, I need Tableau to implement some of the standard Fiscal Calendar types that finance departments typically adopt, such as 445, or 454. There is an explanation here in on Wikipedia.
I would love to be told that I am wrong, and that there is a simple work-around.