I realized, suddenly and months later, that I was over-complicating the compression system for auto-scaling the world as the PCs level by using a chart lookup.

This system should have pretty much the same effect in making the world seem a little less striated into exponentially greater power levels, but be easier to remember. It also makes the PCs’ level more relevant, as it can be keyed into mechanics like Action Points.

Tier Descriptions

Tier Types of NPCs Approximate
PC Level
0 Mooks and commoners N/A
1 Minor threats and skilled townsfolk N/A
2 Local opponents and early rivals 1-3
3 Local Lieutenants, regional opponents, and very skilled townsfolk 4-7
4 Local bosses, regional lieutenants, national opponents, and local leadership 8-11
5 Regional bosses, national lieutenants, global opponents, and regional leadership 12-15
6 Global lieutenants and global leadership 16-18
7 National bosses 19-20
8 Ancient/Godlike lieutenants Mythic
9 Global bosses Mythic
10 Ancient/Godlike bosses Mythic

Using Tiers

Player characters start at Tier 2 and gain approximately five increases in tier throughout their careers. Tier increases should occur around the levels where they gain an ability score increase, but in-play this can be saved for significant accomplishments rather than automatic at level.

Every NPC in the world has a tier as well. Unlike PCs, the tier of the NPCs rarely changes (usually only for significant events like the PCs turning an ally into a cohort or otherwise bestowing increased relevance on an NPC). Instead, compare the NPC’s tier to the PC’s tier, and apply the difference to the PCs’ level to generate the NPC’s level. For example, if an NPC is Tier 5, while the PCs are level 3 (and Tier 2), he’s CR 6; once they reach level 18 (Tier 6), he’s now CR 17.

This scales the world for the reasons explained in the original Compression post linked above: the PCs feel like they’re growing more powerful relative to threats in the world without the dissonance of trivializing revisited individuals. At level 1, mooks are CR 1/3; at level 16, those same mooks are CR 10 and probably less of a threat than they were at first level but much more dangerous than they’d be if they stayed CR 1/3. Similarly, if the adventure path is meant to end at level 16 with a fight against a CR 20 boss, that boss is Tier 10 (20-16 + PC Tier 6 at that point); if they somehow take an early shot at him at level 6, he’ll be CR 13 and a huge threat but possibly not an instantly lethal one the way he’d be if he was already CR 20.

Remember that the NPCs with PC ability scores and gear are approximately CR = level, regular NPCs are a CR or two behind their level, and really weak NPCs might even be three CRs behind their level. If you’re using a module, the easiest thing to do is just figure out the Tier at the time the NPC is encountered. If the NPC is two CRs higher than their level, he’s two tiers higher than whatever they are right then. If they encounter him again, remember his tier to scale him up.

As mentioned, tier can be known to the players. It should serve as a pool or bonus for metagame currency like action points. While they may intuit that recurring foes are getting slightly easier when they go up a tier, they’ll immediately feel the extra resources.