In order to calculate a global score for each substance and thereby to rank the substances, the scores against each of the three criteria were grouped into a table, as shown below.
The scores (Si) awarded against each criterion where then multiplied by the median weighting score awarded to each criterion. As shown in table the weighting scores are as follows:
- 40 for hazardous properties
- 40 for exposure characteristics
- 20 for public concern
The aim of the weighting is to reflect the relative importance of the three separate criteria as dimensions to be considered in the prioritisation exercise. The weighting was decided by key HBM4EU partners by means of an adapted Delphi methods. For further details on this methodology, please consult the report on the stakeholder consultation and mapping of needs.
The sum of the weighted scores then gives the global score for the substance of concern.
The results of the first ranking of substances on the short list are provided in the initial ranking tables.