An endangered species is a species of organisms facing a very high risk of extinction. The phrase is used vaguely in common parlance for any species fitting this description, but its use by conservation biologists typically refers to those designated Endangered in the IUCN Red List, where it is the second most severe conservation status for wild populations, following Critically Endangered.
I measure my happiness 2 ways. 1  Through a (random and irregular) process of self reflection.  2 Catching myself being happy and remembering the last time I caught myself being happy and trying to determine the time between them.
But to the question-HOW can happiness be measured. It can't be, nor should we try to. Happiness starts with an acceptance of reality, an genuine acceptance of the self, compassion for others and being present in every moment.