Every scenario has a tier range and many have associated subtiers. Tiers indicate which character levels are legal for that scenario. If a PC’s level does not fall within the tier, that character cannot legally play in that scenario.
Within each tier, PCs or pregenerated characters should be used in the subtier in which they fall whenever possible, but they may be adjusted up or down, based on the Average Party Level at the table, as outlined below. For scenarios with more than two subtiers, characters must be in adjacent subtiers to play together.
In order to determine which subtier a mixed-level group of PCs must play in, calculate the group’s Average Party Level (APL).
APL = sum of character levels/number of characters
Divide the total number of character levels by the number of characters in the party, rounding to the nearest whole number (this is an exception to the usual ‘round down’ rule). If the result of the Average Party Level calculation ends with 0.5, the players should decide whether to round up or down.
Scenarios are designed for six characters and contain methods to adjust for tables with four players.