I've been testing this on and off for days now, and I cannot figure out what it is that determines when/if you get experience for you follower's kills.

At first, I figured it was a "you must do X amount of damage to gain credit", which seems to be the most "consistent" answer but there have certainly been times where I have done absolutely nothing and still gained full XP for their kills. Not 10 minutes ago I equipped Piper with a gatling laser, 10 fusion cores, and let her clear several different areas with zero assistance from me. Raiders, no xp. Super Mutants, full XP, Gunners...about 70/30 no/yes.

Not exactly definitive results, and this isn't the first time I've tried this. Just for extra info, I have each of the companion perks (Inspirational?), and have tried numerous followers with all manner of builds, and still see similar trends.

So, is there something I'm missing or is this just an inconsistent experience?

On a bit of an aside, I really don't understand the point of their xp stealing to begin with. Why is the payoff for taking the time and caps to properly upgrade our companions nothing but less experience for us? It seems so counter intuitive, as if they are discouraging any involvment with companions outside of using them as packmules. Stranger still that you gained XP from companions in New Vegas, but they opted to remove this in this title. DIfferent devs, I know, but it just makes so little sense to me.

Anyway, thoughts, opinions?