One of the critical characteristics for living and working in extreme environments the dependency on the habitat, its technological capability as well as the sociospatial framing.
Inhabitants who are exposed to remote and hostile environments, not only must overcome the challenges posed by the dangers and limitations imposed by the particular environment itself, but also experience significant distress from being confined indoors and isolated from civilization and social contact.
Thomas M. Fraser suggested "that habitability can be considered as the equilibrium state, resulting from man-machine-environment-mission interactions which permits man to maintain physiological homeostasis, adequate performance, and psycho-social integrity".
Important characteristics of island societies which have previously been overlooked are, amongst others, the extreme seasonal shifts in human pressure, the need to define distances in time, the intricate business ecosystem of islands, and the transition to renewable, locally produced energy.
The tool includes 45 indicators grouped into seven areas that can be used to test the habitability of an island society.