I'd like to produce a model that uses very coarse inputs and produces similarly coarse outputs.
For example, if I were estimating personal sources of wealth I might say that in a given year:
There is a high likelihood that I will earn a moderate salary. There is a trivial chance that I will get a high lottery payout. There is a small chance I will inherit a large amount of money. Therefore... Salary = b * m = m Lottery = t * b = t Inheritance = s * b = s Total = m + t + s = m Where the values are either big (b), moderate (m), small (s), or trivial (t).
This example is far from perfect but describes how I'd like the front end of the model to look. Obviously there is quite a lot more work required at the back end to ensure that the calculations are coherent.
Is there a name for this kind of model? Or a branch of mathematics that would be useful to draw upon?
The approach probably looks weird, and not very useful when we could just use numbers instead, but there are a few things in its favour:
- Simple to operate
- Intuitive verbal descriptions of input and output quantities
- Easier for non-mathematicians to gain insight into the reasoning and model structure
- Keeps the focus of analysis on big picture (rather than getting drawn into considering small differences that may be an artefact of input measurement error)