While most of traditional assessment is based around quantitative metrics, qualitative metrics may be equally necessary in providing understanding related to sustainability.  The nature and the character of aspects of sustainable chemistry are not always reductionist exercises. The renewability of a feedstock, the toxicity of a molecule, the environmental justice implications of siting a factory, market acceptance of an energy technology etc., may all have qualitative aspects that are critically important. While qualitative metrics may be less rigorous and involve integrative systems thinking that is outside traditional analytical frameworks, it is possible that they are more closely linked to the interconnected nature of sustainability systems and goals as outlined in the United Nations Sustainable Development Goals.