How are Para medals decided?

How are Para medals decided?

Events with Para specific medals presented in New Zealand are often raced as multi-classification races - i.e. Para swimmers of all classifications swim together.

Medals for multi-class races are simply decided by which swimmer is closest to the world record of their classification. 

Previously Swimming New Zealand has used a percentage of world record calculation to determine the medal winners, however we are in the process of switching to points (which is in essence the same thing) to align with what World Para Swimming practices.