Average Score Per Taxon

The Average Score Per Taxon (ASPT) equals the average of the tolerance scores of all macroinvertebrate families found in a river, and ranges from 0 to 10.

Usually once BMWP (Biological Monitoring Working Party) and ASPT are calculated, the main difference between these two is that ASPT does not depend on the family richness. It can also used in conjunction with the EK quota to get an assumption of the ecological status for a region by examining many locations throughout the river.