Thursday, 29 August 2013

D&D Next Monsters: Part 9: XP Curves & KpL...

While this blog does not contain material published by Wizards of the Coast it does contain materials summarized and extrapolated from the D&D Next playtest packets. By continuing to read this blog you are consenting to the terms of the Wizards online playtest agreement, which you can view at dndnext.com.

Surf looks at monster XP progression....

So +Jonathan Black asked +Mike Mearls about the discrepancies between low, mid and high level character progression. Specifically "Why does it take more xp to go from 10 to 11 than 11 to 12?". Mike didn't answer, but this raised some questions about monster XP progression in my mind, so I decided to take a look...

 

PC Progression

LevelXPDifference
100
2250250
3950700
42,2501,300
54,7502,500
69,5004,750
716,0006,500
825,0009,000
938,00013,000
1056,00018,000
1177,00021,000
1296,00019,000
13120,00024,000
14150,00030,000
15190,00040,000
16230,00040,000
17280,00050,000
18330,00050,000
19390,00060,000
20460,00070,000

First up let's take a look at what Jonathan is talking about. Let's take the PC progression table and subtract the previous level's value from each level. This gives us the XP a character needs to gain to go up to the next level.

Now to gain a level we expect that we should need to gain more XP than we needed to gain last level. Or at least the same. But not less. Now take a look at the differences at levels 11 & 12.

The only explanation for this is human error. I believe this is a simple transposition mistake. If we swap the two values around then everything is perfect. This is the kind of think I'd expect Wizards of the Coast to fix quietly.

Swapping these two values works perfectly. In mathematical terms there isn't much real impact and it's probably not worth the headache of getting your whole group to understand the issue and agree that XP to reach level 11 should be 75,000 rather than 77,000. But if you are keen that's the only change required.

Of course, working through this got the old mental cogs turning...

 

PC Progression vs Monster XP

Looking at PC progression got me thinking about the relationship between it and monster-at-level XP values. There's a relationship between the two, regardless of how loosely Wizards of the Coast have defined it. Obviously the PC progression chart helps us here, as does the Average column of the encounter design table (which is essentially the XP for one Average monster for that level). One of the design concepts of D&D Next also tells us what to expect. That is "...fast advancement at lower levels with more gradual advancement at mid- and high levels".

 

Monster XP Curve

Average Monster XP by Level

Simply graphing the Average monster XP by level shows us that it's all over the place. I'd say "quite out of whack at higher levels". The trendline on the graph shows the kind of progression I'd expect.

What we see is that after level 11 there's a lot of XP that's just way higher than we'd expect. One could argue that this doesn't matter because the encounter math is built on the assumption that monster XP values use the same table. And running some quick pivots show that's the case.

LevelEasyAverageTough
1102040
24060110
370100200
4110160320
5150230460
6220330650
7290440880
84006001,200
95107701,500
106701,0002,000
118501,3002,600
121,0801,6003,300
131,4002,1004,100
141,7002,6005,200
152,2003,4006,700
162,9004,3008,600
173,6005,50010,900
184,7007,00014,000
195,9008,90017,700
207,50011,30022,500

And yet this argument misses something important - the impact to PC progression. These higher XP rewards, and higher associated encounter XP budgets, mean that PCs level up with fewer fights than if the correct values were being used.

When we are levelling up too quickly we feel that the game is too easy. So these over-curve XP values likely play a part in the feeling that D&D Next combats are too easy at mid and high level. Not that they are the only factor.

Regardless of whether it's necessary, it is pretty easy to determine the "right" values. We just add an extra column to our graph, copy the current values into it and then adjust them until each point sits on our trendline. We can even sprinkle in some of the usual RPG industry "rounding magic" to make the final table a bit more palatable to the human mind (people like to see zeros on the ends of longer numbers).

Which gives us a handy new encounter budget/monster XP chart.

Now, let's see if it proves useful...

 

Kills Per Level

Kills per Level (Current) Kills per Level (Revised)

If we subtract the XP needed to reach the next level from the XP needed to reach this level and divide the result by the XP value of an Average monster of this level we learn the Kills per Level (aka Kills/Level aka KpL) for this level. We can trivially do this for every level and then graph the result.

And the result is really interesting!

Yes, the values are scattered. And yes, we can correct this pretty easily simply by using our new Encounter/Monster XP table (see the "Revised" graph). But what's interesting is the curve! Wizards of the Coast seem to have decided that from level 10 we need to have far fewer fights each level. I'm guessing that's because they didn't plan to release many mid- or high-level creatures during the playtest and only planned to get a feel for what the epic tier of play was like.

And I reckon this is a factor in the feeling that the higher levels of play are too easy.

 

Correcting It...

LevelCurved TailPlateau
100
2250250
31,1001,100
43,1003,100
56,5006,500
611,80011,700
719,70019,300
830,60029,800
945,60044,200
1064,80062,600
1189,60086,400
12121,000117,000
13159,000155,000
14207,000204,000
15266,000265,000
16341,000344,000
17433,000443,000
18550,000570,000
19697,000732,000
20883,000936,000

There are pretty much two options for correcting this. The first is simple, we halve the XP budget and XP value for encounters and creatures over level 10.

The second option is not something I'd ordinarily recommend, but the more I look at it the more convinced I am that it's the right way to go. It's an option you'd have to sell to your group - updating the PC progression table. Generally I prefer options the DM can silently use behind the scenes, but if PC progression is at fault then that is what is most appropriate to correct as other corrections will have side effects. Some of which won't be immediately obvious.

If we do this we need to decide how we want our progression to look. For my money I like a "curved tail" curve that starts like the current curve, it curves up to 25KpL at level 8, from there gently curves down to 21 KpL at level 20. The other option I'll present is a "plateau" curve which also starts similarly, curving up to 24 KpL at level 8, from there ever so gently dropping down to 23KpL at level 20. Again, I applied a little rounding to make the final numbers more natural for humans.

Then again, none of this matters if you don't use the PC progression table... Like my own group. When the DM simply decides how often everyone levels up this whole article become a moot point.

But it was an interesting moot point...

 

 

Check back next week for the Part 10: Final Packet Analysis...