Monday, October 10, 2011

On Expected Treasure and XP

Tom Moldvay wrote in his D&D Basic Rulebook (1981):
... most of the experience the characters will get will be from treasure (usually 3/4 or more) [p. B45] *
I think that many old-school players take this as a statement of original design intent regarding the old D&D treasure types and experience system. I'm going to disagree with that, and claim: (a) this statement by Moldvay is descriptive and not normative, and (b) while it's accurate for Moldvay's B/X rules, it does not match other editions of D&D. (Note: All discussion below is in terms of by-the-book D&D gold-standard economy.)

Arneson's OD&D

Let's look at OD&D first. Below you'll see a table of all the hostile monster types (those appearing in dungeons) from Vol-2, p. 3. Each has its standard number appearing, experience point value (per Sup-I, Greyhawk), and expected value from its treasure type (including the requirement that the in-Lair % chance be rolled; as stated on Vol-2, p. 23). Then a ratio for expected value of the treasure versus monster XP is made. (Download full .xls spreadsheet here.)

The end result: Over all of these monster types, there is a GP:XP ratio of 1.5; that is, only about 3:2 in favor of the treasure XP. A clear majority of monsters actually give more XP from the monster than the treasure (about 20 of 30). Note that there are two extraordinary outliers: Dragons (ratio 8:1) and Medusae (ratio 23:1!); if you remove these two outliers from the list, then the overall ratio dips to just 0.8 (i.e., actually less treasure than monster XP). Another way of looking at this, perhaps -- roughly 40% of all the available treasure in the game comes from Dragons, and until the PCs are high enough level to be hunting dragons, their XP will mostly not be coming from treasure. (If played purely according to these random charts.)

Side observation -- The majority of most treasure value comes solely from the Jewelry component. By my calculations, almost all of the OD&D treasure types have between 55% to 85% of their average value coming from Jewelry (average 70%; with outlier Type G, a low 20% of its value from jewelry). Or in other words: If you miss the Jewelry component roll for a treasure type, then you've missed about 2/3 of the nominal value of that treasure type, on average. Or again: Making the Jewelry roll approximately triples the total value from any treasure type.

Other note -- You might look at the XP example of the troll in Vol-1 ("7,000 G.P. + 700 for killing the troll = 7,700" [p. 18]) and say, "hey, that's evidence that OD&D gives about 10% XP for monsters". Except that the example is doubly impossible from the listed monster/treasure tables: (a) trolls number appearing is 2-12 (1 being impossible), and (b) troll treasure type D has at best 1-6 thousand gold pieces (7,000 being impossible). According to my stats, the average result would be to get 7 trolls for 4,550 XP (7×650 per Greyhawk) and a total 3,743 gp value, i.e., as we're saying, expect more XP for the trolls than the treasure. (Also: This example refers to trolls as being "7th level", whereas the monster levels in Vol-3 only go up 6th, so the example is pretty disconnected from the rest of the rules.) Keep in mind that if we used pre-Greyhawk XP (HD×100), then things would be even more skewed in favor of the monster XP.

Moldvay's B/X

Let's try this again for Moldvay's B/X rules. Now, two huge changes will occur at this point. One: The large-scale numbers appearing have been dramatically reduced for the numerous humanoid types (usually dividing by about ten; e.g., men/bandits from 30-300 in OD&D to 3-30 in B/X, etc.). Two: The Lair % statistic has been entirely removed, so presumably any time the larger number of creatures appears, they get their full treasure type valuation. See the results of that below (or spreadsheet for this here):

Now: Over the same core hostile monster types, the GP:XP ratio is close to 3; i.e., a 3:1 relationship of treasure to monster XP -- or in other words, exactly the "usually 3/4" from treasure as Moldvay asserted (see quote at top). Most monster types (about 25 of 30) do indeed give more XP from their treasure than from the monster. While dragons and medusae still have excellent GP:XP ratios, now the far and away outlier is actually Men, with an astounding 108:1 ratio in favor of their treasure! (Analysis: Type A is an excellent type of treasure;the number appearing was divided by 10 from OD&D; and the frequency of treasure was multiplied 6-fold by dropping the low 15% Lair chance.)

Side observation -- Moldvay presents a list of "average values (in gold pieces) of each treasure type" [p. B45], and Moldvay's averages are extremely accurate. (They match very nicely to my numbers in the linked spreadsheet.)

Other notes -- In general, the following are all copied directly from OD&D: (a) Monster treasure types. (b) Treasure type contents (with the addition of new electrum & platinum categories). (c) Monster numbers appearing, for types other than the multitudinous humanoids. (d) The XP values for monsters. (e) Dungeon unguarded treasure tables. However, gem and jewelry values have distinctly dropped by abandoning parts of the generation procedure (gems in a batch "increasing value", and jewelry high-end exceptional rolls).

Treasure in the Dungeon

Now, the preceding was based just on looking at the core "numbers appearing" and "treasure types" from OD&D, which are generally supposed to be just for wilderness encounters. We might ask the obvious question of what's supposed to be the case in the dungeon, but the situation there is enormously more murky. Unfortunately, all of the classic versions of D&D leave this issue almost entirely unspecified and in the realm of pure DM fiat.
  • OD&D states multiple times that monster numbers should be scaled to size of the PC party (Vol-2, p. 4; and Vol-3, p. 11). The listed numbers should be "primarily only for out-door encounters" (Vol-2, p. 4); and treasure types are only applicable to "those cases where the encounter takes place in the 'Lair'" (Vol-2, p. 23). In the dungeon, all we are given is that creature numbers are "modified by type" (Vol-3, p. 11; more discussion here). Dungeon treasure might possibly be generated on level-based tables (Vol-3, p. 7), although in later editions of D&D, those tables are generally indicated as for unguarded treasure only. (Note: If used for that purpose, then the average GP:XP is even lower, 0.7 by my calculations, i.e., about the same as the treasure types sans dragons: spreadsheet here.)

  • Holmes D&D keeps the same treasure types; he removes all of the numbers appearing in the monster entries (esp., all of the hundreds of humanoids); but he adds specific numbers for the dungeon wandering monster tables (usually on the order of 1d6 or so). But as far as dungeon treasure goes, he gives a short nod to OD&D and then punts to another product entirely:
    The TREASURE TYPES TABLE (shown hereafter) is recommended for use only when there are exceptionally large numbers of low level monsters guarding them, or if the monsters are of exceptional strength (such as dragons). A good guide to the amount of treasure any given monster should be guarding is given in the MONSTER & TREASURE ASSORTMENTS (available from TSR or your retailer). [Holmes D&D, p. 22]

  • Moldvay's B/X still maintains the same treasure types; and he merges the numbers appearing into two high/low categories (but again: dividing the truly large numbers by about 10). He says that the higher numbers are for when "met in in the monster's lair (home) or in the wilderness", and regarding treasure types, "in general, treasure is usually found in a monster's lair (home)" [p. B30]. This linkage is reiterated again later:
    Treasures A through O are large, and generally only for use when large numbers or fairly difficult monsters are encountered. The lairs of most human-like monsters contain at least the number of creatures given as the wilderness "No. Appearing" (the number in parentheses). [p. B45]

  • However, having said that twice so far (that full Treasure Types are for large, lair-wilderness numbers only), Moldvay then contradicts this with his dungeon stocking procedure. Having rolled a small, random dungeon-wandering sized encounter, he says, "If treasure is in a room with a monster, use the Treasure Type for that monster (given in the monster description) to find the treasure in the room.)" [p. B52] Zounds!

  • Frank Mentzer's DM's Rulebook basically copies the Moldvay language on treasure types. "When the Treasure Type is a letter from A to O, that should only be the treasure found in a full lair (the Wilderness No. Appearing -- the number in parentheses in the monster description)" [p. 40]. However, his dungeon-stocking procedure apparently switches back to the OD&D rule -- it deletes any mention of monster Treasure Types, and instead references the same short level-based random treasure table: "The amount of treasure can be determined by using the random Treasures Table..." [p. 47] (I guess I would consider this a proper fix to the overly-generous and contradictory Moldvay rule.)

So we see that in most versions of D&D, the preponderance of the evidence is that Treasure Types are actually not to be used for standard dungeon-based small numbers of monsters, but only for large wilderness-equivalent numbers in the "lair". Which is a rather significant misstep, based on our standard dungeon-centric use case. But that data is the best we have for expected XP ratio from treasure/monsters -- and as we've seen for OD&D, if we use the dungeon level-based treasure tables, then the ratio is even lower (more from monsters than treasure). In neither case does it seem like this was an advance design consideration.

(Notice that I haven't worked out AD&D numbers for this discussion: it would be quite a bit harder, since in that work Gygax switched from one-letter-type-per-monster to a mixture of several different combined letters per monster. That said, I'm assuming that the ratios are about the same as in OD&D, since the numbers appearing, in-lair %, etc., are generally copied directly from that work. With the possibly large wild card of awarding XP for usage of magic items.)


Here are some conclusions that I would offer, based on this evidence:
  • Arneson probably didn't plan out any statistics like this in advance for the original system. And probably Gygax never actually used random treasure tables at all in his games. (I'd say they're both notorious for not actually using the published rules; and the vagueness of dungeon numbers and treasure speaks to the lack of any specific system for that in the first place.)

  • Moldvay, however, shows an exquisite awareness of the average results produced by the treasure table system (as evidenced by his correct 3/4 ratio statement; and listing the correct average values for each treasure type, unique to his rules). That said, this could not have been an advance design decision, because he simply copied all the legacy types and valuations from OD&D (and does an across-the-board deletion of Lair %, and reduces the larger numbers appearing).

Let's accept that the D&D treasure and experience amounts were not initially designed with any particular ratio of XP from treasure versus monsters. But let's say that you want that, to promote certain desirable types of gameplay (such as rewarding treasure-acquisition from stealth and trickery, for example). Then you might select from one of the following possible options: (a) Follow Moldvay in deleting in-Lair % checks, and dividing humanoid lair numbers by about 10. (b) Ignore the in-lair dictums for treasure types entirely, and award the whole Treasure Type even for small numbers like 1-6 orcs. (c) Boost the XP value from treasure, perhaps awarding 10 XP per GP, or something like that (also accelerating advancement). (d) Shift all of the XP away from monster-killing, adding the same value to their treasure-acquisition awards (if that's what you want to promote, might as well go whole-hog, eh?)

* Thanks to Tavis and Kipper at the ODD boards for reminding me where this statement came from.

And additional thanks to UWS Guy and DHBoggs for informing me in the comments that the OD&D treasure type system was the work of Dave Arneson.

(Photo by Falashad, under CC2.)


  1. Since the treasure section of 0d&d was areneson's work, it would be illustrative to check what the FFC says on dungeon stocking.

  2. Also XP from magic items counts as treasure, any number crunching that doesnt include this will be misleading

  3. There's an AD&D rule that the treasure type values are for the maximum number of monsters, and if you meet fewer monsters, then the treasure type should be proportionally smaller.

    Suppose we take that suggestion and use it with the Moldvay rule to take the treasure type for the monster for in-dungeon encounters -- in other words, in the dungeon, you meet 6 orcs, they'll have 1/10 of a full type D treasure. You meet 3 orcs, they'll have 1/20th of a full type D.

  4. One other factor that most folks have missed over the years is that, while Moldvay's base numbers on group encounters in the dungeon were reduced by a factor of 10 on the "No. Encountered" line, he says in the intro to the monster section that, "Monster lairs in wilderness will usually be 5 times the number normally met in dungeons." (pg. B30)

    So the treasure figures for Men are not quite that skewed.

  5. Fascinating Dan thanks for doing this! Objection though to the "Gygaxian OD&D" label in this context. As I and others have pointed out before, the economics of OD&D is almost completely Arneson and Blackmoor. The prices, costs, expenses, taxes and so forth are straight from Dave. Off the top of my head, the only thing I know of that Gygax significantly altered in terms of expenses were the costs of making magic items. Thus your statement;

    "•Gygax probably didn't plan out any statistics like this in advance for the original system. In fact, he probably never actually used random treasure tables at all in his games. (I'd say that he's notorious for not actually using the published rules; and the vagueness of dungeon numbers and treasure speaks to the lack of any specific system for that in the first place.)"

    is probably true for Gary. Its also worth noting that in Arnesons conception of the XP award system, a great deal is made of "Prizes", that is the magic items recovered, thus several hundred xp for potions and several thousand for magic swords, etc.

  6. Thanks for the comments, guys.

    UWS Guy/ DHBoggs: I'll trust you guys that the OD&D treasure stuff was Arneson's work and revise the blog (appreciate it!)

    However, there aren't any XP awards for magic in any of the editions mentioned here (OD&D, Holmes, Moldvay B/X, etc.) If you're saying that's in FFC, then that's intriguing.

  7. Glaurung_Quena said: "There's an AD&D rule that the treasure type values are for the maximum number of monsters..."

    Actually, what I see in the 1E MM is, "treasure types are based upon the occurrence of a mean number of monsters... adjustment upwards might be called for if the actual number of monsters encountered is greatly in excess of the mean." [p. 5]

    So that's the same as what I assumed in the analysis here. Maybe that language was revised in the MMII, as I recall?

  8. Re: "the overly-generous and contradictory Moldvay rule" about treasures generated during random stocking.

    Not sure it's a contradictory rule. Check out the example of random treasure generation for room 4 on page B56. He does use the treasure type in the monster description, but also scales it down based on the proportion of hobgoblins in the room relative to the minimum hobgoblin lair size.

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  10. Guy Fullerton said: "Check out the example of random treasure generation for room 4 on page B56. He does use the treasure type in the monster description, but also scales it down based on the proportion of hobgoblins in the room relative to the minimum hobgoblin lair size."

    Great point (and matches what Glaurung_Quena suggested above). Of course, that isn't included in any of the text instructions elsewhere in the book.

  11. I'd argue it's simply a natural consequence of using the two particular passages together. The B45 passage informs you about *how* to use a monster's treasure type, and the B52 passage informs you about *when* to use it.

  12. Unfortunately with Arneson, XP for magic items is mostly anecdotal, without specific crunch attached. Magic Swords were his first major treasures back in ’71 which cost a base 1000 GP. Gygax, in the FAQ does give crunch for XP as 1000 for a +1 sword, scroll of spells at 500 points + 100 for 6th level spell, and “ a potion is worth between 250 and 500 points.”
    These are pretty close to the cost of making or buying these items. So the principle in operation here seems to be that of awarding the GP value of a magic item as XP. Might be worth doing a separate analysis under that assumption to see how it works out.
    Just to be clear, I wouldn’t make the claim that the OD&D treasure tables are precisely as he gave them to Gary, as its entirely possible that Gary fiddled with them, or maybe he didn’t (but I bet he did). I know that Arneson had another version of these tables in his unpublished OD&D revision.

  13. Well 0d&d clearly states that a dungeon will have 33% of the rooms with monsters, but 50% of the rooms will have treasure.

    More importantly, xp from monsters slain is divided equally between pc and npc hirelings and henchmen, but treasure is massively squewed towards PC's. I break down the numbers in the thread over at 0dd74.

  14. UWS Guy: I see very different numbers for room content. OD&D Vol-3 (p. 7) gives treasure 3-in-6 (50%) for rooms with monsters; it's only 1-in-6 for other rooms (17%). Total would be 5/18 = 27.8% rooms with treasure.

  15. Woops, don't know how I missed that. That will lessen treasure, though preceeding paragraphs to say to place "several" important treasure (with or without monsters guarding it), how much is of course up to the referee.