Well, are they? Over a wide range of fall distances, impact surfaces, character sizes, etc.? I dunno. But here’s one interesting piece of data – an expert’s claim, anyway – that we can use to match one real-life situation against the results generated by an RPG simulation, and see how the two compare.
So go get your favorite GURPS characters, nonchalantly lead them to the rooftop of a four-story building, and push them off! Let’s see how many survive.
Falls and the LD50
The AV Club article “Allow this trauma surgeon to ruin a few of your favorite action scenes” introduces a video in which trauma physician Dr. Spiros Frangos reality-checks the hurts he sees in movies.
Case in point: When Tom Cruise drove his car off of a parking garage floor in Mission Impossible: Ghost Protocol, Dr. Frangos says the character should not have walked away easily (if ever). Maybe. This is actually a hard one to call, as it’s an unusual fall, what with the car and seat belt and air bag and all that.
But for the far more common case of a fall victim who’s not handily ensconsed in a steel cocoon, the good doctor points us to “LD50”, or the “height at which 50% of patients are likely to die” – and names 48 feet (16 yards), or about 4 stories, as the LD50 height. (And how was this information obtained? Anecdotally and not experimentally, we hope!)
That’s something we can place up against game rules! We’ll have to make assumptions, of course; namely, that the data behind the LD50 claim represents people of all ages and sizes, and thus “average” people overall. Which means we’ll be dropping an average HP 10, HT 10 GURPS character, with no special traits assumed. We’ll also have to ignore real-life complications for which we don’t have information – e.g., to what extent the fatality statistics are lessened by landings on softer surfaces, or are worsened by head-first impacts (something not explicitly made an outcome in GURPS rules). And on the game rules side, we’ll ignore the complications of mortal wound results (which make proximity of medical care a factor) and optional rules like bleeding.
Those considerable caveats notwithstanding, where damage and death are concerned, this LD50 stat sounds like one of the cleanest claims we could test in-game.
So what’s the damage?
Turning to Basic Set 431 . . . Hey, this is easier than I expected! That page’s example of a fall does all the work for us. It uses an HP 10 victim (“Bill”) and a fall of 17 yards, which yields the same damage as the 16-yard fall that we want.
Bill meets the ground at 19 yards/second, which would be (10 x 19)/100 = 1.9d damage – but hard pavement doubles that to 3.8 damage, which rounds up to 4d crushing
That’s an average of only 14 damage, though. Subtracted from HP 10, our own Bill is left at HP -4 – he’s hurt badly, unconscious, and just plain out of action, but not dead. A very high damage roll could kill him, but we’re surely not getting our LD50 with this fall. (A fall onto soft ground, meanwhile, isn’t likely to even render Bill unconscious!)
Dialing up the hurt
So, what adjustment would make a GURPS 16-yard fall better match reality? At least another 50% damage, I’d think. If the GURPS rules meted out 6d damage for this fall, our Bill would take an average 21 damage – just enough to push him over the negative HP line, and thus forced to make a death roll. Which, at HT 10, means a 50/50 chance of dying – exactly what LD50 calls for.
But that’s still a bit low, as nearly half of those 6d damage rolls will fail to reach Bill’s death roll threshold. (We’re only looking at a rough LD25 or so here.) Perhaps 7d is better, yielding an average 24.5 damage and placing Bill’s HP neatly between -1xHP and -2xHP – solid “roll HT or die” territory. Low damage rolls will still fall under the death check threshold, but equally high damage rolls will force two death rolls. On balance, it sounds like we’re giving Bill a proper coin-toss chance at future adventures.
I’ll leave it to anyone interested to fiddle with the exact distribution of results and come up with a precise calculation of the damage dice that would yield a perfect 50/50 chance of survival in this fall. (Edit 2019-06-02: See the comments for a good argument that +100% damage does the job properly.) I’ll just eyeball things with this: At least where 4- to 5-story falls are concerned, if GURPS boosts its hard-surface fall damage by at least 50%, and as much as 100%, the results would enter the ballpark of this doctor’s claim about LD50 height. As it is, GURPS awards relatively low damage in this fall, perhaps as low as half what it (arguably) should be.
But that’s not too shabby, as RPG simulation goes! This lowballing of damage is even a welcome thing for PC survival, as they scale cliffs, leap chasms, and wage battles on rooftops. Sure, it means the bad guys also get off a bit easy when the PCs toss them off of heights – but a dropped mook who’s “merely” knocked out is still out of the fight (and is soon out of it for good, if the PCs are vengeful “finish the job” types).
Well. That was mildly amusing, if not terribly useful. Heading back to the good doctor, I like how he ends the video:
As a trauma surgeon, when I go to the movies, I’m always thinking about the realism of particular injuries, to the fact that sometimes it ruins the movie for me.
I think we can appreciate that! Because as a gamer, when I go to the movies, I’m always (well, often) thinking about how the screen action maps to game simulation. To the extent that even a discussion about movie action gets me rolling dice in my head.
You too, maybe?