The number of players in your game has important structural effects beyond just how many orcs you need to include in a given dungeon room. While itís impossible to offer a universal rubric for determining the ëcorrectí number of players for a PbP game, it is worth setting out and discussing some common factors that should be considered when deciding how many players your game should have.

Game system

If the game system proscribes or presumes a certain number of players (e.g., Cthulhu Confidential (one player), Better Angels (minimum 2 players), etc.), then you probably have at least part of your answer, unless youíre prepared to do some system hacking. Similarly, but less definitively, some systems just function best mechanically in a certain player range - indeed, most games are either implicitly or explicitly designed to function best with 3-5 players, and varying too far from that can create mechanical difficulties.

Another factor to consider is the complexity of the system. Running a rules-heavy game for a large group isnít necessarily harder, but it does require more work: not just for the GM, but for all of the other players who also have to consider the mechanical impacts of what all of their co-players are doing.

The gameís initiative system is also something to be considered. Reality being what it is, large groups of players and systems with highly-structured and important initiative systems tend not to mix well in PbP, because there will always be a player who isnít ready to go when their turn comes around. (Weíve briefly spoken before about some ways to address problems with initiative in PbP games, and will probably cover it again at greater length.)

Game setting and premise

Some game settings and premises work better - in the sense of having more fictional plausibility or better tone control - with certain size groups. The setting and premise of a game are, however, the most easily mutable factors about a game. In other words, you can easily adjust the setting and premise to the size of a group, or vice versa.

Just remember to consider doing so, because games with the same setting and premise but different group sizes are going to feel and run much differently. Consider, as an example, a traditional game about dungeon delving. Running that game with one PC as a lone operator will feel much different from one with a pair of PCs which will feel much different from the same game run with a squad-sized unit of PCs.

Player spotlight

We spend a lot of time discussing the disadvantages of PbP play, but one of its advantages (and one probably worth its own column) is that its easier to share spotlight time in a PbP game than around a table, for the simple reason that its possible to have multiple simultaneous scenes occurring in PbP in a way that is physically just not possible at a table.

That said, any game is, from time to time, going to be more ëaboutí one player than another. Certain types of mechanical, setting, or character elements are going to foreground one player over another, and thatís entirely fine - itís how things are supposed to work.

All else being equal, the more players in your group, the less any particular player is going to be in the spotlight. Also, the more players in the group, the more work the GM has to do to make sure that the spotlight moves around at a reasonable pace and that nobody gets left out of the circuit. (Players have some responsibility here, too, of course.)

Player responsibility

The other side of the coin with respect to spotlight time is player responsibility.

Weíve spoken before about how momentum (that quality of the game that makes a player want to make their next post) has a sort of distributed social responsibility function. In other words, thereís a pressure - usually implicit but sometimes explicit - on each player to post in order to keep the game going for the entire group.

This pressure tends to have less effect in bigger groups, because the same responsibility for keeping the game running is spread over more individuals. In other words, in a single player game, thereís no question over whether the game will keep moving forward if Player A doesnít post. With eight players, Player A may feel more comfortable not posting, because they think that Players B through H will keep things going. The obvious problem being, of course, that Players B though H think the same thing about Player A and each other player. (This is an infinitely more benign example of the bystander effect.). This problem is particularly acute when the spotlight is on (Or is perceived to be on) some other player.

The way that all of this cashes out is that smaller games tend to be more susceptible to player loss, while larger groups tend to be more susceptible to momentum loss.

GM mindshare and time

The simple truth is that, for a given level of game quality, a bigger group takes more GM time and effort. While this is probably obvious, GMs may forget to consider it in their excitement to get a new game up and running. Resolving the mechanics of 4 PC actions just takes more time than 3 PC actions, and keeping track of 4 PCsí worth of backgrounds and plot hooks just takes more effort than 3 PCsí worth. Donít let your reach exceed your grasp.