In order to discuss abstracts such as health or damage, the TSA and Frontiersmen use Louise Sterkman's Tactical Point System. Originally created for virtual games and training simulators, the system is a mathematical calculation that attempts to build a useful reference point for how much damage is done to a target, and how much health a marine (or in the new system, an alien) possesses relative to these weapons. The system assumes each marine has 100 'points' of health (given Frontiersmen health conditioning, there is little variation between marines), and 50 points of armor. All weapon stats and alien abilities are calculated from this baseline. This can lead to some seemingly gruesome statistics, like determining the strength of a Skulk's bite, based on the average number of attacks it takes to inflict fatal damage on a marine in field armor. This number has been determined, after accumulating first-hand data, by the following calculation:

Average (successful) attacks required = 2.
An un-upgraded marine has 50pts of armor, which absorbs 30% of damage.
So, the Skulk is doing at least 71 points of damage per attack (30% of 71= 50.4).
Further refinements have led us to assume the bite attack is closer to 75 points.