Occurrence frequencies calculation

Occurrence frequencies can be provided as data or computed from occurrence patterns. For a food and substance, they are computed by collecting all occurrence patterns of this food and summing up the frequencies of the occurrence patterns containing the substance. In the unlikely case that the total frequency of the occurrence patterns of a food exceeds 100%, then a rescaling is applied first. If the sum of the frequencies does not sum up to 100%, the interpretation of the remaining unspecified percentage can be designated as either “no use” or “all use”. In the the first case it is assumed that none of the substances occur on this remaining percentage. In the latter it is assumed that all of the substances occur on this remaining percentage. This choice is available as the setting associate the unspecified percentage with no-occurrence for foods with at least one specified occurrence pattern.

Depending on the setting apply occurrence pattern percentages, occurrence frequencies can be computed in a crisp form in which the occurrence frequency is either 0% or 100% or as percentages ranging from 0% to 100%.