Standard

Standardizing things such as strength is easy. Just pick some simple method such as how much weight can that individual pick up.

In this case, we needed a way to standardize the calculation of endurance in the sense of how much physical damage a lifeform can take. For these tests, we picked the obvious choice of how many 14 inch rounds it takes to kill the chosen lifeform. For each 14 inch round survived, the lifeform gains 1 hit point (or HP).