Flawed House Rule: Double-Rolling Hit Dice
I’d imagine that most Dungeon Masters have made their own tweaks and variants to the Dungeons & Dragons game system. The most popular of these “house” rules often spread to games run by other DMs. Unfortunately, popular doesn’t always mean good.
One example of such a flawed rule is double-rolling hit dice, wherein players roll twice for each hit die and take the highest result. I got this one from my former Dungeon Master, and used to use it in my early games. It’s clearly popular among powergamers, and at first sight there’s nothing wrong with the rule.
Mathematics disagrees! Statistically, double-rolling increases the average result of hit dice, making characters tougher. A fighter’s d10 rises from an average 5.5 to 7.15, an increase of 30% before Constitution, and with 16 Constitution still around 20%. The problem with this, as opposed to something like higher ability scores, is that you throw hit points out of whack with everything else in the system. Your saves and offensive abilities are not improved, only your capacity for taking damage.
In this case, it’s especially bad because more hit points has the only effect of letting you last longer and relax a little in combat, taking an element of risk out of the game. This has the effect of making combats last longer and making the game more dull, the latter of which is a Bad Thing. If you scale up the opponents’ hit points by double rolling to compensate, it just exacerbates the effect and makes extra work for yourself, and if you scale up the opponents’ challenge ratings you’ve simply made the game more deadly because your players’ offensive and saves don’t match their hit points.
Beefing up your player characters for its own sake isn’t necessarily good. If it just makes the game easier for your players, it’s not necessarily going to make the game more enjoyable.
July 21st, 2007 at 11:01 pm
Well, I agree with what you are saying, but what happens to the player who is just plain unlucky and happens to be the group’s ‘tank’. What if he rolls 1 or 2 on his 1d10 hp roll for 2nd and 3rd level? This in its own right is unbalancing. Maybe a compromise would be to have the player roll two hit die rolls and average them. This will change the ‘bell curve’ to produce more average results and thus counter the argument either way. A player would have to be real lucky to get max hp or min hp.
I have heard all kinds of House Rules on the subject from ½+1, two rolls, and even max past 1st level. I guess it boils down to how the DM wants to run his campaign. For instance, PCs with max HP will run into 6 Orcs instead of 4 for instance.
Thoughts of a D&D addict,
Regards
August 21st, 2007 at 7:46 am
Our GMs usually play that we can choose to have a second roll only if the first result is low relative to the dX eg can reroll a d10 if the first roll is 1, 2 or 3.
Also, if you reroll you have to take the new result.
Using your example above, the average for d10 (assuming you always take the reroll) would go from 5.5 to 6.55 - still 20% higher without Con bonuses - but it also doesn’t distort the distribution as much (chance of a 10 is 13% vs 19% under the 2-roll system).
September 22nd, 2007 at 12:39 am
I DM a house rule in an Eberron campaign where a player can burn an action point for that level if she rolls a 2 or less on a hit die. I don’t know ow it affects my choice of challenges for them but it feels fair enough.
I have never heard of the “best of two” house rule and I am glad. Your argument makes perfect sense.
November 15th, 2007 at 9:23 am
We had a reasonably detailed argument about this once. After some discussion, we realized the real goal is to improve the bad rolls, i.e., bring up the lowest percentile of characters, while not inflating the average much. Some good methods for accomplishing this are the following (the second is a generalization of poster 2’s approach)
(1) For dN hit die, roll twice, add a random 0 or 1 (decided, e.g., by rolling d6/4, round down), and divide by 2 (round down). This has the same mean and median as the usual roll dN approach, but substantially reduced variance. Some players don’t like this because it makes the high numbers rare as well.
(2) Roll dN. The player can choose, once, to re-roll this result. The optimal strategy for minimized variance is to re-roll anything lower than N/2 (i.e., re-roll a 1 for d4, a 2 or 1 for d6, etc.). Roughly speaking, this inflates average hit points by N/8 while doubling the hit points of the bottom 15th percentile of characters.
November 15th, 2007 at 10:59 am
My house rule is to give everyone max hit dice for their class. But of course all of the bad guys and monsters get maxed too ;)
November 23rd, 2007 at 7:41 pm
I agree the above method is no dice.
We use the double rolling hit dice rule, however, if a roll is rerolled the player must keep the second result.
December 4th, 2007 at 9:12 pm
If you’re worried about the fighter rolling low, but want to include some randomness, I would think the best way would be to subtract 2 from the max roll to gain +1 hp. ie. barbarian could do d12, or d10+1, or d8+2, d6+3, d4+4, or take 6. Minimum roll d4. Then add con bonus.
January 12th, 2008 at 10:44 pm
One interesting one way to allow for a certain minimum hp is to have players who roll below average simply take the average. Thus, your players will always have at least the average. Of course, the most important is to take this into account when making enemies or challenges. As for max hp, it’s a risk, but can be worthwhile if done properly (I’ve seen close to this, with increased challenges, but we ended up retconing anyway).
January 13th, 2008 at 12:17 pm
The low roll is a problem, slightly offset by the fact that a normal fighter type should have at least a +2 con bonus (this varies, I know, but generally). The strategy we’re using at the moment is that you can either take (N/2)+1 for DN, or roll it and accept the result. This unfortunately discourages anyone with a low hit die from ever taking the chance, while leaving the character with high hit dice with a dilemma (being a former mathematician, I’d just take the (N/2)+1 even with a high hit die, assuming 20 levels).
My personal choice would probably be some variant on Andrew’s suggestion: I’m not convinced that low hp characters are very viable, and I don’t think the game makes enough allowances for them.
January 21st, 2008 at 10:35 am
In levels one to three I think it’s a good idea to let PCs have above-average hitpoints. From a GM perspective, your choices for fun, appropriate challenges are severely limited if a character can be killed by just one unlucky blow.
In my current campaign, I gave everybody max hitpoints at level one and let them keep the best of two rolls at level two. For every level up after this the rule is one optional re-roll, must keep second roll.
I guess technically, monster hp should be rolled using similar rules for balance purposes … but then I hardly ever roll monster hp anyhow: They have average HPs, but get more or less on the fly, depending on how combat goes and what best serves to dramatise the story.
January 21st, 2008 at 10:01 pm
In the 3.5 game I’m in (not running) we re-roll if the roll is under the midpoint.
While this could be quantified mathematically as N/2 + dN/2, we just roll and figure it, then re-roll.
We’re still early in the game, so the GM might change it later on.
Though I like the N/2+1 for the Bard and Sorcerer (or other d4 classes).
January 23rd, 2008 at 9:46 pm
I’ve been using the roll twice method that my friend has been using for his game. This is also an example of house rules being contagious :) If I had to do it all again, I would give you the first half of your HP, and roll the other half. As in:
d4 = 2+1d2 | d6 = 3+1d3 | d8 = 4+1d4 | d10 = 5+1d5 | d12 = 6+1d12
This means that everyone has at least a hair above average hit points, and still some randomness. There’s obviously more randomness at the top end (barbarians with 7-12, wizards with 3-4), but I will never run a game where I’ll allow a barbarian to roll a 3 for hit points, period. It’s one thing to roll poorly in a critical situation, but it’s yet another to miss out on one of the prime features of your class due to a single die roll, and be stuck with those consequences for the rest of your life.
May 20th, 2008 at 1:55 pm
In the past few campaigns I’ve used this method:
Maximum hit points for the first 3 levels, there after roll for hit points as normal but always reroll 1s.
My tank players will usually be alright with an occasional 2 or 3 rolled and the mages always love it since they have HP closest to average with this method. For my group of 4 years this has worked fine. :)
Of course as a DM I do have back up plans for those who tend to roll low consistently and fall behind the curve… finding an occasional “Potion of Perminant +1d6 HP” in a treasure trove is not a bad way to bump up those lagging scores. :)