I know population increases taxpayers (and in turn revenue), give more people to send on colony ship and make excellent cannon fodder... I mean soilders for troop transports. But how do they figure in production and stuff like that.

What generates more money 10B people with 2 Markets, or 20B people with 1 Market (not neccessarily those numbers but you get the image). And more so, how does research on production play out (again, the x people to y factory/lab or 2x people 1/2y factory/lab example).

I ask because I had planets with only 5B people being Manufacture or Scientific paradises, while planets with 10s of Billions fairing worst than fledging colony. I have feeling while I am stabbing in the dark I loosing alot of efficiency in my colonial management.