Welcome to Guidance, Private Sanctuary’s source for tips and techniques for the Pathfinder Roleplaying Game, written by Everyman Gamer Alexander Augunas. Today, we’re going to be talking about an alternate system for designing encounters based off of XP rewards. This article heavily utilizes the topics discussed in the Math Behind CR article, so I advise all readers to check out that article before tackling this one.
The CR system is designed to be relatively painless. You calculate the average level in your party and compare it to a set numerical term to decide how hard an encounter would be for your PCs. This system has been a staple of 3rd Edition gaming since it’s inception. But what if I told you that CR as a measuring tool was a larger unit that can be collapsed into a smaller, more accurate tool? Would you believe me?
For today’s topic, XP rewards. Why are they more valuable to the GM than the players?
In GM’s Guide 1, we talked about the mathematics behind the Challenge Rating (CR) system. One of the major topics we discussed is the correlation between CR and XP rewards. Specifically, two prominent formulas appear when you analyze Table 1-12: Experience Point Rewards. Those formulas are CR + 2 = 2(XP) and CR + 4 = 4(XP). I prefer to call these formulas the Rule of 2 and the Rule of 4 respectively. We also looked at the Average Party Level (APL) system vs. the CR system and figured out how to convert a PC party’s APL into CR, which revealed that encounters up to APL +4 are heavily slanted towards the PCs.
The Fifth Element
One of the breadcrumbs that I left in the previous article was the idea that the APL calculation formula in Chapter 12 of the Pathfinder Roleplaying Game Core Rulebook was wrong. Specifically the idea that adding a fifth member to your party does not affect the group’s APL. It’s time to prove that wrong with very simple mathematics. For the purpose of this demonstration, I will be using 1st level PCs again, which are CR 1 and worth 400 XP.
- APL 1 (4 PCs) = 400 XP * 4 PCs = 1,600 XP
- APL 1 (5 PCs) = 400 XP * 5 PCs = 2,000 XP
- APL 1 (6 PCs) = 400 XP * 6 PCs = 2,400 XP
All right, now quickly compare these values to Table 12-2: Experience Point Awards. If you look carefully, you’ll see that the 4-Man Band’s XP value is perfectly budgeted for a CR 5 encounter and the Six-Man Set’s XP value is perfectly budgeted for a CR 6 encounter. Looking at Table 12-3: High CR Equivalencies in the Core Rulebook flat-out tells you that this is what you should expect; 4 creatures of the same CR increases the encounter’s CR by +4 while 6 creatures of the same CR increases the encounter’s CR by +6. Note, however, that Table 12-2 has no references to encounters worth 2,000 XP and Table 12-3 has no reference to the CR increase associated with having 5 creatures of the same CR in an encounter. This is due to the exponential nature of the XP reward system; remember how we noted that the only patterns in Table 12-2 are the Rule of 2 and the Rule of 4? This is an effect of the XP rewards being specifically designed with the Rule of 4 in mind.
What Time is It? Pillaging Time!
So, why do our rules work? Its actually a very obvious reason; XP totals were designed to be divisible by 4. From CR 1 and higher, the XP rewards progression needs to be divisible by 4. Why? Look no further than the iconic adventuring party.
The “Sacred Quartet” of Pathfinder is a party consisting of four characters; a fighter, a rogue, a cleric, and a wizard. This is plastered all over 3rd Edition and Pathfinder’s marketing; the Pathfinder RPG Beginner Box set is the first product that comes to mind, but most Adventure Paths feature four iconic characters. The reason the number 4 is so highly entrenched into 3rd Edition gaming has everything to do with the Rule of 4 as it pertains to encounter design; the game assumes that you are a four person party, so the XP rewards need to be able to be divided evenly by 4. Take a look at Table 12-2 again; every encounter CR 1 and higher is specifically divisible by 4. The only exception to this rule is certain fractional encounters (i.e. CR 1/3), but creatures of fractional CR are either designed for group encounters or not intended for true combat at all. For example, if you place three CR 1/3 encounters together, you total 390 XP, which is just about equal to the CR reward of a CR 1 encounter (400 XP). Not perfect, but pretty darn close considering that you’re essentially trying to divide the baseline 400 XP into three equal groups.
I want to redirect your attention back to the previous section, where we looked at the XP value of an APL 1 party with 5 members: 2,000 XP. We verified that no encounter on Table 12-2 lists 2,000 XP as its XP reward and Table 12-3 does not list the CR increase that occurs for a Five-Man Band. Why is this? Well, a CR 5 encounter is worth 1,600 XP and a CR 6 encounter is worth 2,400 XP. That’s a discrepancy of 800 XP, and the Five-Man Band sits directly in between them at 2,000 XP; 400 XP above CR 5 and 400 XP below CR 6. Effectively, adding a fifth player to your group increases your party’s Challenge Rating by half a CR. The million-dollar question is, “Is this a big deal?” The answer, of course, is heck yes. Adding another player to your party without compensating for his presence in any way, shape, or form further slides the XP rewards in the party’s favor. Below I’ve reproduced our APL / CR discrepancy chart from the first GM’s Guide to help visualize the problem.
- APL 1 (1,600 XP) / CR 5 (1,600 XP) – Equal
- APL 1 (1,600 XP) / CR 4 (1,200 XP) – Challenge has 75% of party’s XP
- APL 1 (1,600 XP) / CR 3 (800 XP) – Challenge has 50% of party’s XP
- APL 1 (1,600 XP) / CR 2 (600 XP) – Challenge has 37.5% of party’s XP
- APL 1 (1,600 XP) / CR 1 (400 XP) – Challenge has 25% of party’s XP
The values shown above are the unmodified APL/CR/XP values for a 4-player party of 1st level PCs going up against encounters ranging from CR 1 to CR 5. Now I’m going to modify those values to show what happens when you put a 5-player party of 1st level PCs against the same encounters, unmodified to account for the additional party member as suggested in the Core Rulebook.
- APL 1 (2,000 XP) / CR 5 (1,600 XP) – Challenge has 80% of party’s XP
- APL 1 (2,000 XP) / CR 4 (1,200 XP) – Challenge has 60% of party’s XP
- APL 1 (2,000 XP) / CR 3 (800 XP) – Challenge has 40% of party’s XP
- APL 1 (2,000 XP) / CR 2 (600 XP) – Challenge has 30% of party’s XP
- APL 1 (2,000 XP) / CR 1 (400 XP) – Challenge has 20% of party’s XP
As the numbers show, in terms of resources and available actions, adding a fifth player has huge repercussions on an encounter system that is already heavily slanted in the PCs’ favor. Mathematically, that fifth player really softens up higher-difficulty encounters rather than the lower difficulty ones; in practice, your players will often steamroll your average-difficulty encounters anyway, so that fifth player only makes the tides of death wash over enemies slightly faster. It is in encounters that would normally be long and gruesome that the additional player helps most.
In short, you cannot expect the addition of an additional player to your Pathfinder Roleplaying Game adventure to have absolutely no consequences upon the difficulty of your game.
Balancing Around Rewards
So, how can we compare the unavoidable power creep that comes with the territory of adding a fifth friend to our Pathfinder campaigns? We all want to do it; some of the most notable fighting forces in media have been Five-Man Bands. Though it would be obnoxious to add in half-CRs to Table 12-2, it is neither difficult nor impossible to balance encounters around the addition of a fifth party member. Doing so is a somewhat time-consuming process, but you’ll really thank yourself when you understand the mathematical reasoning behind it.
Earlier we discussed how the assumed party is comprised of four characters: a cleric, a fighter, a rogue, and a wizard. This is why all XP rewards associated with CR 1 and higher in the game are divisible by four. The system is thusly designed so the iconic party can equally share all XP earned from a given encounter. To this end, adjusting an encounter is surprisingly simple. All you need to do is figure out how much XP each player is expected to contribute to completing an encounter. Because XP is typically awarded to all party members equally, the game assumes that all party members contribute equally to an encounter, and when they don’t the game assumes that the GM will design other encounters so all party members contribute equally to the adventure overall in some way.
Let’s take our CR 1 party again, a Four-Man Band with APL 1, and have them face off against a CR 1 encounter. In this encounter, our Four-Man Band will earn 400 XP for successfully completing the encounter, which is divided equally between all four members upon completion. 400 XP / 4 players = 100 XP per player. This means that each player is expected to contribute roughly 100 XP of his or her own resources to the encounter.
Now, let’s bump up the encounter to a Five-Man Force with an APL of 1 and pit them against the same CR 1 encounter. In this encounter, our Five-Man Force will earn 400 XP for successfully completing the encounter, which is divided equally between all five members. 400 XP / 5 players = 80 XP per player. As noted in the previous section, the fifth player allows his four comrades to contribute 20% fewer resources to the combat, as he is assumed to use his resources in the engagement.
But what if we wanted to preserve the game’s intended difficulty? Well, we know that the game intends for all players to spend 100 XP of resources fighting a CR 1 encounter, so adjusting that number for a Five-Man Force is remarkably simple; just increase the value of a CR 1 encounter from 400 XP to 500 XP by adding 100 additional XP of challenges. For example, Table 12-2: Experience Point Awards informs us that a CR ¼ opponent has an XP reward of 100 XP. This means that adding a CR ¼ opponent to a CR 1 encounter allows each of the five players to earn 100 XP upon completing the encounter; all five players are now expected to contribute roughly 100 XP of resources when completing the encounter.
Using this system, you can easily tune the difficulty of encounters for your adventures, even if your players are different levels. Want a CR +3 encounter? Then determine the amount of XP that all players should contribute for an encounter of that individual PC’s CR (which equals their class level) plus your intended difficulty. For example, if I have a party of four 7th level characters and one 5th level character, I could run a CR +3 encounter for them by totaling up the XP that each 7th level character should contribute to a CR 10 encounter (9,600 XP / 4 = 2,400 XP, times 4 PCs is 9,600 XP) plus the amount of XP that the 5th level character should contribute to a CR 8 encounter (4,800 XP / 4 = 1,200 XP) for a grand total of 10,800 XP. From there, I use my Pathfinder Bestiaries to pick any creatures for my encounter that strike my fancy so long as their total XP reward equals (or is very close to) 10,800.
In the spirit of making things easy, I’ve created a handy reference chart that shows you the XP that a single player contributes to a party, based on the PC’s CR. It ranges from 1st level to 20th Level/Mythic Rank 10 (effectively a CR 25 character) and includes detailed remainders and examples of how to properly utilize the table. You can download this document by clicking on the following link: GM Guide 2 – XP (Table Doc).
That about wraps up the second installment of the GM’s Guide. Next week, we’ll be looking at the Action Economy; what it is and why you should care. Until then, what are some techniques that you use when designing encounters for abnormally large or small groups of PCs? How do you keep a large group of PCs from feeling marginalized by one another’s presence and how do you keep a small group of PCs from feeling overwhelmed by large threats? Did you feel I covered this topic sufficiently, or do you have any additional questions remaining? Leave your answers in the comments below!
Alexander “Alex” Augunas has been playing roleplaying games since 2007, which isn’t nearly as long as 90% of his colleagues. Alexander is an active freelancer for the Pathfinder Roleplaying Game and is best known as the author of the Pact Magic Unbound series by Radiance House. Alex is the owner of Everyman Gaming, LLC and is often stylized as the Everyman Gamer in honor of Guidance’s original home. Alex’s favorite color is blue, his favorite Pathfinder Race/Class combination is kitsune bard, and his favorite pastime is summoning and sealing bargains with unknowable and incomprehensible entities for power and glory.