What is raid size based on?

[antibodee]

Is it based on time, colony size, research, or a combination?

[prongssage]

i think its based on the wealth of the colony

[Goo Poni]

Combination of time and wealth. I'm pretty sure even if you kept an arsenal of weapons big enough to keep one of the raider bases in supply for a couple weeks at the start of the game, you'd still only get a single guy attack at first. But then the next raid is probably gonna be like, 6 guys in power armour and sniper rifles in hand.

[TheSilencedScream]

Time and wealth are two of the biggest contributing factors, as well as number of colonists and time since last injury/death (the game is a little more lenient, usually, if someone just died).