I have to admit I've been both tempted and reluctant to try and answer this question. Tempted, because I like helping players, and enjoy sharing game design discussion. Reluctant, because I deliberately obscured the mechanics of the game as part of the design. Whats more, the stats are likely to change as the game is in development. And in some cases, a complete understanding of the mechanics would be beyond the scope of a short answer.
However, I believe I can share some useful info. The game has some skills which are currently only used as part of encounter/scavenge responses and crafting recipes. Such skills include hacking, botany, trapping, lockpicking, electrician, and mechanic. There is no passive effect imparted by these skills at this time.
The rest have passive or mechanical effects, and without quantitatively listing every detail, they include:
- Medic - improved healing rate (i.e. sterilization techniques and knowledge, etc.) and more detailed stat bars on conditions screen
- Hiding - ability to hide is more effective, camp concealment stat visible on camp screen
- Melee - better chance to hit in melee combat, higher wound severity, better defense in combat, can leg trip in combat
- Eagle Eye - can see one hex further than normal, light and line of sight permitting, and can detect hidden things easier
- Tracking - can spot older tracks than normal, and hide tracks is more effective
- Athletic - less fatigue per move, can run away from all opponents in battle, can run further on map before run moves deplete (no longer grants one extra move per turn, though)
- Tough - higher pain threshold, immune system effectiveness, and resistance to wounds, ability to head-butt in combat
- Night Vision - no longer available as a skill, but does what it says (e.g. goggles, dogmen)
- Strong - can carry more without being encumbered, melee attacks are more damaging, can create obstacle in combat
- Ranged - Higher chance of hitting with a ranged weapon
- Slow Metabolism - food and water intake rates reduced, healing rates slightly reduced
Traits do the following:
- Fast Metabolism - food and water intake rates increased, healing rates slightly increased
- Myopia - can see one hex less than normal, and detecting hidden creatures is harder
- Feeble - melee attack severity is lessened, can carry less
- Fragile - physical wounds, pain, and infections are more effective on you, healing is slower
- Insomniac - difficulty falling and staying asleep (need more fatigue or higher comfort levels to sleep)
Some abilities also affect AI morale, such as strong or tough. Having either of these will make you seem tougher to an enemy, making you less attractive as a target. Similarly, having either of those makes them more confident.
Finally, I'm forgetting a lot. This is just from memory, since there's a chain of variables I'd have to trace for each one to know for sure. There are some hard-coded effects, too. But generally, they work as described above. More importantly, they're designed to do "what you'd expect," meaning there are some effects which I tangled in there based on our perceptions of those abilities (like the morale effects).
And, of course, I reserve the right to be wrong, and change my mind at any time :)