In my research (such as it is), there are two basic events that stop a fight:
1. A significant central nevrous system (CNS) hit (i.e. brain or spinal cord)
2. Shock due to blood loss.
In the case of a CNS hit, the effects are more or less immediate and profound. DRT, or at least really incapacitated.
For #2., it is intuitively obvious that you bleed faster through big holes than small ones. Does this scenario favor the notion of over-penetration (shot through and through, e.g. with hardball) vs. a wide internal wound channel via HP, but no exit? I'll leave it to those who've BTDT, but speculatively, I suspect one bleeds out faster with more holes.
There's also the aspect of structural damage, e.g. busting out a hip or other supporting structue, which may put them on the ground, but not necessarily out of the fight. This supports the adage that anyone worth shooting, is worth shooting [at least] twice, or, keep shooting till they quit twitching. And usually, when there's major structural damage, there's usually a lot of blood loss.
Bottom line, though, remains the same as itever was: first and foremost, shot placement is paramount. A .22 in the eye works better than a .454 nick in the ear. Use enough gun - that is what you shoot well with confidence.
Thus endeth the sermon.