How can I encourage population balance between two factions?

Question

I'm making a game in which players must choose between two factions after reaching a certain level.

PvP and PvE are not influenced by this choice as it's mostly for role play and the sense of belonging to a community (and perhaps seasonal events).

The two factions can communicate. Preferably, guild members must be in the same faction and it should be impossible or not easy to change factions.

I fear that if a faction starts to have the majority of players, new players will want to join it to play with their friends or have more guild choices.

How could I mitigate or prevent that? Are there alternatives?

Answer 1

A few thoughts:

• An economy can help keep balance. If one faction has more access to an item than another, and if that faction is underrepresented, then those items will be more rare in trade. This will motivate more players to join that faction to get the more rare items.
• Since the factions are mostly for role-playing and story, the choice should be based on what "represents" them (personality test?). A good, simple example of this is Pokemon Go. People got passionate about their team based on just a couple words describing the ideals. There was little difference in the factions themselves. With this kind of personality-based classification, people will often contrast themselves from their friends to pick the opposite faction.
• As long as there is plenty of communication between factions, the problem of friends grouping up should not matter much. In fact, you might see the opposite, where someone chooses the faction opposite his friend to see what else the game has to offer. This is what I would do, because then between the two of us, we could do everything. This might be more tricky if those factions are actively warring against each other, but since you said they are not, I'd recommend allowing teams to form built of people of both factions (Not necessarily a guild, but maybe a team for missions).