Also, it could be further connected to things like ethics or civics - maybe Spiritual empires tend to have more children than technocrats, maybe universal health care improves on max numbers a bit, maybe slaver empires breed their pops like cattle. The point of this system is that galactic pops are limited to whatever level you think your machine can handle, you can increase your pop growth speed by simply playing well and thus being able to build ringworlds (or launching an exterminatus or two), and the devs can give whatever bonuses they feel necessary for game balance to developing or regressing empires. You're way behind? Rubber band activate!), normalize these scores (divide a score with the sum of all empire's scores - or use softmax if you want to handle negative scores) to get normalized_score, similarly get normalized_pops = empires_pop / total_galactic_pops, and finally calculate empires_required_growth = required_growth * (normalized_pops / normalized_score). You just achieved spaceflight? Here's your baby care package. Built a gene hospital? Good for your pop numbers! You've recently purged filthy xenos / disgusting meatbags? Have first dibs on the living space you made available. Just a regular planet or habitat? Fine, but not by much. You have a ringworld/gaia world/ecumenopolis? Your relative share goes up. You could then calculate a score for each empire (You exist? Here's a 1 for you. Suggestion: since the goal is to limit the total galactic pops to a level the engine can handle, just let the player define that limit (and perhaps even the base growth) in game settings and then make the required growth tend to infinity as total pops approach that limit - something like required_growth = base + ( 1 / (max_pops - current_pops)).