
1. Re: Chainladder table calculation  Question 1
kettan Aug 15, 2013 2:00 PM (in response to kettan)The formula below works, but has hardcoded values for the dimensions.
What I need is a dynamic formula without hardcoded conditions.
IF ATTR([Development Year]) = 1 THEN
WINDOW_SUM(SUM(IF [Incident Year]<=2011 THEN [Amount] END), FIRST(), 0) /
WINDOW_SUM(SUM(IF [Incident Year]<=2011 THEN [Amount] END), FIRST(), 1)
ELSEIF ATTR([Development Year]) = 2 THEN
WINDOW_SUM(SUM(IF [Incident Year]<=2010 THEN [Amount] END), FIRST(), 0) /
WINDOW_SUM(SUM(IF [Incident Year]<=2010 THEN [Amount] END), FIRST(), 1)
ELSEIF ATTR([Development Year]) = 3 THEN
WINDOW_SUM(SUM(IF [Incident Year]<=2009 THEN [Amount] END), FIRST(), 0) /
WINDOW_SUM(SUM(IF [Incident Year]<=2009 THEN [Amount] END), FIRST(), 1)
END

2. Re: Chainladder table calculation  Question 1
Shawn Wallwork Aug 15, 2013 3:17 PM (in response to kettan)1 of 1 people found this helpfulJohan I spent a bit of time looking at this and didn't get anywhere. I mention this because I didn't want you to think none of us tried.
Cheers,

3. Re: Chainladder table calculation  Question 1
Dan Huff Aug 15, 2013 3:22 PM (in response to kettan)2 of 2 people found this helpfulJohan
The attached has the answer correct. This is a very complicated calculation. I am happy to add captions explaining each of the calcs but for now I just wanted to give you your solution.
Look for an update later tonight or tomorrow.
Hope this helps,
Dan

4. Re: Chainladder table calculation  Question 1
kettan Aug 16, 2013 3:03 AM (in response to Dan Huff)Thanks Dan,
These are precious formulas for learning table calculations and hopefully also the first step toward a workable chainladder IBNR for the task at hand.
I will prepare a question 2 which will build on your calculations and also share an Excel spreadsheet with working formulas for easy comparison.
Jóhan

5. Re: Chainladder table calculation  Question 1
kettan Aug 16, 2013 4:22 AM (in response to Shawn Wallwork)Thanks Shawn, this was heartwarming.
 Getting feedback without a workable solution feels much better than being ignored.
 Knowing it probably can't be done or will be very timeconsuming also makes it easier to switch to a task with high impact and low effort rather than spending more time on a task that needs high effort and possibly no impact.
 It also makes me feel less stupid that I am not alone having difficulties with table calculations.
That said, I will be among the first in the line to buy the book "Tableau Table Calculations for Dummies" when it hopefully is released.
Jóhan
Ps. 2 points for helpful answer which improved my mood