Quite often the uncertainty related to the amount of a specific
input or output cannot be derived from the available
information, since there is only one source of information
providing only a single value, without any further information.
A simplified standard procedure has been developed
to quantify the uncertainty for these (quite numerous) cases.
The simplified approach includes a qualitative assessment
of data quality indicators based on a pedigree matrix, that
takes pattern from already published work (Pedersen Weidema,
Wesnaes 1996).