Classification of impacts is made on a three-point scoring basis. Scores are combined by experts to give an overall assessment, which is heavily risk-oriented. Determine relevant effects caused by a process or product. Determine the extent of the effect in the region being studied - this is the normalisation value. Effect divided by normalisation value equals total contribution.
All contributions are dimensionless.
Multiply the effect by a subjective weighting factor. This stems from the critical volumes approach. Emissions are weighted in relation to environmental quality targets. Results are calculated in dimensionless ecopoints which are subsequently summed to give a single number, or ecoscore. The system covers all impact categories including resource depletion and waste disposal to land fill.