Result range

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Revision as of 18:26, 23 May 2010 by Jouni (talk | contribs) (moved Result domain to Result range: Range is more correct term for this.)
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The result domain of a variable contains all possible values that the result of the variable may get with probability P>0. The result domain is restricted by logical (the number of actual individuals must be an integer), rational (concentration cannot be negative or above 1000 g/kg), and observational (TCDD concentration in humans has never been observed to be above 144000 ng/kg fat) statements. The utility of result domain comes from the dependencies to other variables. Child variables are probability distributions conditional on their parents. If the result domain of the parents is defined and more or less unchanged, it facilitates the definition process of the children. The conditional probability distribution of a child is only defined for the parent values within its result domain.

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Should 'Result domain' be a sub-attribute of 'Definition' in a variable? Alternative solution: it is discussed under 'Data', because in practice, the result domain is based on Data. Third alternative: it is put under 'Result', maybe as a sub-attribute; this is not a good idea, because the result domain has implications on e.g. 'Formula', and it is not good if the result affects Definition.

→ Because clear understanding does not yet exist, the attribute structure is not changed, and the result domain is described under 'Data'. R↻

Scope

How can a plausible result domain for a variable be found? What are the criteria for inclusion or exclusion of a particular value or range?

Definition

Rationale

In expert judgement, it is a common practice to define the result domain by calculating the difference between the fractiles 0.05 and 0.95, extend that by k % (k is often 10 % or found by optimising), and subtract it from and add it to the fractiles 0.05 and 0.95, respectively.

In open assessment, all values are included in the result domain by default. A suggested procedure is to exclude any range X that passes a critical argumentation about the exclusion. The argumentation has a statement of the following form: "It is impossible that the result of the variable may be within range X." If the statement is accepted, X is excluded from the result domain. R↻

Procedure

All values are included in the result domain by default. Any range X that passes a critical argumentation about the exclusion will be excluded. The argumentation has a statement of the following form: "It is impossible that the result of the variable may be within range X." If the statement is accepted, X is excluded from the result domain.

See also