2009-09-03

OD&D Saving Throw Statistics

Here's a series of charts I compiled, comparing the various OD&D saving throw categories (click image to expand).

These graphs chart the saves at every individual level in OD&D, and also insert linear regression lines ("trend lines", or "lines of best fit"). They incorporate all the data from levels 1 to 15. I think this highlights certain patterns which are not obvious in the tables (granted the differing ways the class levels are grouped), and may even disabuse a few common misconceptions.

One of the first things to be seen is how the class save values are grouped (Fighters in blocks of 3 levels, Clerics 4, Wizards 5). Some of us would like to smooth this out from the table values, permitting a small improvement every level or so (as suggested for fighter to-hits in the AD&D DMG, or the Lakofka/Gygax Dragon article noted here) -- so the trend lines are useful for that.

A second thing is that wizards (magic-users) tend to have a shallower trend line, improving more slowly than the other classes. This is partly because there is another higher-level category for wizards (levels 16+) which is not shown here. Ultimately wizards end up with saves as good as (or better than) the other classes, but that doesn't occur until the very high levels off these charts.

Now for some more specifics. Fighters and Clerics are extremely close in almost all their values and trends, to the extent where I'll simply regard them as effectively the same. Similarly, in the last chart, saves vs. Spells are practically identical for all the classes at all levels; at most a difference of +/-1 in the trend at any level. Saves vs. Stone are somewhat more mixed; the trend lines actually cross (Fighters start out the worst, then become the best), but are so closely packed that we may as well treat them as basically the same, as well.

Finally, some differences. Wizards (and hence Thieves, as per Greyhawk) are clearly, consistently deficient in their Death and Wands saves from levels 1-15. Also, while starting out fairly close, Fighters have a particularly steep (beneficial) trend line in Breath saving throws. Therefore on average, wizards are at -3 when compared to Fighters across all these categories (Wands, Death, and Breath; technically average -2.67, -2.67, -3.47 respectively). Even clerics are at a -2 average penalty when compared to fighters in the category of Breath saves (-2.33, to be exact).

It's interesting that if you take Fighters as the basic character class (including all monsters), the baseline saves differ, on average, by precisely 1 point per category. That is, starting with the last category of Spells, Breath is at +1, Stone at +2, Wands +3, and Death +4 (again speaking in terms of the trend line intercept parameter; you can also see it immediately in the top row of the OD&D table itself).

The trend lines move downward with an average slope of -0.6 over all saves and classes (with a range of from -0.45 for the shallow wizard lines to -0.8 for the quickly advancing fighters vs. breath saves). If we think about smoothing out the curves with a simple formula (instead of using the tables directly), we might think about giving a bonus of half-the-level as a pretty good estimate. Of course, in my OED rules editorial, I felt even that was too complicated, and simply rounded it off to d20+level (beat 20+), plus the various modifiers noted above.

12 comments:

  1. I have looked into this subject quite vigorously in the past and noticed more or less the same trends as you are mentioning here. It is also interesting to contrast the original saving throw progressions with the advanced ones. I produced some conversion charts for Swords & Wizardry a few months ago:

    Saving Throws (1974)
    Saving Throws (1979)

    You can also find some interesting discussion on the subject over at Knights & Knaves:

    Saving Throws in Original Dungeons & Dragons

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  2. Hey Matthew, honest question because I'm having difficulty reading your table. For example, in the 1974 table, why are Clerics listed as +5 vs. Death and Fighters +0?

    Looking directly at the OD&D tables, Clerics are almost always within 1-point of fighter death saves (which to me is effectively the same thing). Is this a revision or something for S&W?

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  3. Looks like a transcribing error. The fighter column is backwards, and should read as "+4, +3, +2, +1, +0". There should also be a footnote for Fighter Dragon Breath saves that the bonus becomes +2 at levels 7-12, and +3 at levels 13+. Fighter saves versus Stone should also be noted as +3 at levels 13+. Here is a revised version:

    Saving Throws (1974)

    There are probably other errors, let me know if you spot them!

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  4. Thanks for this work. It makes thinking about class-based save bonuses in S&W somewhat clearer.

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  5. I went over the advanced version as well and weeded out the same errors (cut and paste result). You can check the revised version of the advanced saving throws here:

    Saving Throws (1979)

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  6. Matthew, looks like the errors are now fixed (just looking at the OD&D table here). Thanks for the replies.

    As a friendly critique, those charts are sufficiently complicated that I wouldn't want to use them in play. I tend to not want to deal with rule differences as small as +1 (e.g., everthing effectively matches fighter bonuses except in save vs. spells).*

    The other thing is that it's tricky to use charts like this to compare the strength of different classes. What looks like a cleric/wizard "bonus" is actually overwhelmed by the fighter's faster progression group. For example, it makes it look like wizards are better than clerics at saves vs. spells -- when actually clerics are equal or better than wizards at all levels 1-15.

    (* Aside: Personally, the two main things that prevented me from adopting S&W are (1) the save mechanic, and (2) the class methodology [race-as-class, no thieves, elf rule]. I do recommend my OED rules editorial for the simple but very similar results save mechanic.)

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  7. As a friendly critique, those charts are sufficiently complicated that I wouldn't want to use them in play. I tend to not want to deal with rule differences as small as +1 (e.g., everything effectively matches fighter bonuses except in save vs. spells).

    Absolutely, this was just an attempt to express the rules in a Swords & Wizardry format.

    The other thing is that it's tricky to use charts like this to compare the strength of different classes. What looks like a cleric/wizard "bonus" is actually overwhelmed by the fighter's faster progression group. For example, it makes it look like wizards are better than clerics at saves vs. spells -- when actually clerics are equal or better than wizards at all levels 1-15.

    Oh, they are not supposed to be used for comparison! The comparative charts look entirely different, more like graphs, really, as with the one that appears on the above linked Knights & Knaves thread.

    (* Aside: Personally, the two main things that prevented me from adopting S&W are (1) the save mechanic, and (2) the class methodology [race-as-class, no thieves, elf rule]. I do recommend my OED rules editorial for the simple but very similar results save mechanic)

    Personally, I prefer the single save mechanic, but I know it is not for everyone!

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  8. Matthew, thanks for the reply, sounds like you have your goals well in hand. :)

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  9. I ran OD&D using your house rules, and the Target20 system held up very well for attacking, but I felt it didn't work so well with saving throws. First, given the very static nature of saves, I chose just to express all the saves as plain target numbers, so the players could just roll and compare and immediately report back if they'd made it or not, no arithmetic necessary.

    Also I felt that having the save probability given by "level + save mod" seemed too steep. This means that at 1st level, a player has a 30% chance of passing a save vs death, and a mere 5% chance of passing a save vs spells, while at 20th level this becomes 100% for all saves! I changed it to "5 + 1/2 level + save mod", so saves go from 25-45% at 1st level, up to 75-95% at 20th level

    I know this means some extra work for me if I need to make a save for a monster, but it brought the saves much closer to the OD&D values. It also makes low level characters more robust, and high level characters more vulnerable, which I like more.

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    1. That's very observant, I agree that the Target 20 for saves is a bit less robust than attacks in exactly the ways you mention. Partly I get away with it by mostly running tournament games in the "sweet spot" of levels 4-10 where our methods basically agree anyway. I tend to start PCs these days at 4th level so I dodge that constraint at 1st level and get to use the easier rule. Also, over time I've even dropped the -2 modifier for magic-users in wands/breath/death, since in practice it seemed too punitive.

      So I'll say kudos to you for using the more exact 1/2-bonus-per-level model.

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  10. If you track HD seperately from level, then use HD as your modifier, T20 still works pretty well for saves. I use a S&W style single save, except I give MUs a bonus against spells. I differentiate the classes by class-based bonuses: FM+3, MU +5/+6, CL +5. So my formula is d20 + class mod + HD > or = 20.

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    1. Right, that does work very well. Admittedly I use the Sup-I style linear hit dice with different sides, so generally I don't have those HD numbers available (documented/memorized) in my games.

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