No, that’s a good and valid question and I’m unsure of the answer. At first I thought it was because I had not properly separated out some of the calculations (e.g., I had a single cell that accounted for both number of years to take to become a top charity and number of staff years per year). But once I separated them out (see “Alternate Calculation” in the model), the uncertainty range is still larger for senior staff than all staff, even though the all staff calculation unambiguously includes all the values of the senior staff calculation and more.
So now I think it’s either possible there’s an error somewhere in my model or maybe some of the uncertainty are interfering with each other and cancelling out. I think this second one can happen when you divide two intervals.
Also, the fact that the senior staff number range includes a number close to 0 would create the potential for a very large tail of high impact, which would not be present on the total staff year model which does not include numbers close to 0.
No, that’s a good and valid question and I’m unsure of the answer. At first I thought it was because I had not properly separated out some of the calculations (e.g., I had a single cell that accounted for both number of years to take to become a top charity and number of staff years per year). But once I separated them out (see “Alternate Calculation” in the model), the uncertainty range is still larger for senior staff than all staff, even though the all staff calculation unambiguously includes all the values of the senior staff calculation and more.
So now I think it’s either possible there’s an error somewhere in my model or maybe some of the uncertainty are interfering with each other and cancelling out. I think this second one can happen when you divide two intervals.
Also, the fact that the senior staff number range includes a number close to 0 would create the potential for a very large tail of high impact, which would not be present on the total staff year model which does not include numbers close to 0.