
1. Re: How to compute a custom weighted performance index
Charlie Archer Mar 8, 2016 9:21 AM (in response to Francesco Dall'Asta)1 of 1 people found this helpfulHi Francesco,
Have had a quick go at this and think i have achieved what you've set out for with two calculations.
Weighting (this calculates the weighting for each market):
IF MIN([MKT]) = "A" THEN [Percentage Margin] * 0.6
ELSEIF MIN([MKT]) = "B" THEN [Percentage Margin] * 0.2
END
Combined weighting (this calculates the overall weighting (A+B) and adds this to the Weighting calculated above to get to the final weighting):
AVG({EXCLUDE [MKT]: [Percentage Margin]} * 0.2) + [Weighting]
Does this work for you?Thanks,
Charlie 
2. Re: How to compute a custom weighted performance index
Francesco Dall'Asta Mar 8, 2016 9:52 AM (in response to Charlie Archer)Hi Charlie,
thanks for your answer!
Your calculation is something similar to what I tried. The problem is that the computation are still dependent on filter for Markets. Even if I exclude MKT C in the filter, the calculus does not work.
Also, the IF for the Weighting calculated field you produced, calculates a new percentage margin at row level. This is different from computing an aggregate percentage margin and multiplying it for a constant.
Maybe I should post an excel sheet so you can understand how this index should be calculated?
Thanks by the way,
Francesco

3. Re: How to compute a custom weighted performance index
Charlie Archer Mar 8, 2016 10:00 AM (in response to Francesco Dall'Asta)Hi Francesco  yes if you could send over an example in this case that would be helpful.

4. Re: How to compute a custom weighted performance index
Francesco Dall'Asta Mar 8, 2016 10:07 AM (in response to Charlie Archer)Hi Charlie  OK, I attached the Excel in my original post.

5. Re: How to compute a custom weighted performance index
Charlie Archer Mar 9, 2016 1:49 AM (in response to Francesco Dall'Asta)Hi Francesco,
After some playing around i have replicated the Excel. I'm sure there are a couple of steps that could be missed out here (and there may be an altogether more efficient way of carrying this out), but this gets to the end result.
Thanks,
Charlie

Example _community (CA).twbx 18.8 KB


6. Re: How to compute a custom weighted performance index
Francesco Dall'Asta Mar 9, 2016 2:41 AM (in response to Charlie Archer)Hi Charlie,
Thanks for your answer again. Sorry about that, I am quite new in the forum.. I do not see any attachment to your post.. Is there a way I should see a tableau workbook or something?
By the way, I guess I reached a solution too, however I would be glad to see your workaround since you were so kind to work on it.
In the meanwhile, I'll post mine, maybe somebody in the community might find it useful:
It is possible to compute three different percentage margin at row level depending on the three constant, maybe through a parameter:
CALC MARGIN FOR MARKET A = IF MKT='A' THEN MARGIN * 0,6 ELSE 0 END (only margin measure should be rescale depending on the weight)
CALC SALES FOR MARKET A = IF MKT ='A' THEN SALES ELSE 0 END
You do the same for the market B and A+B and compute the three ratio (Sum(Margin MKTA)/ Sum(Sales MKTA) in order to obtain the percentage margins.
The index would be at the end :
Percentage Margin MKT A + Percentage Margin MKT B + Percentage Margin MKT A+B.
We do not have to insert constant multipliers in this calculation because they are already embedded in the single percentage margin for each MKT.
Thanks,
Francesco