I guess if you super micro pops by sending them to cold planets, then maaaybe it could give some benefit. But in general I find food (pop growth) being much more important, more pops = more of everything.

It's hard to say, lets analyze it a bit without faction-specifics:

- Cold planets can add 2 extra science per pop with the latest science planetary improvement (Citizen Science).

- Cold planets also get 2 extra pop on cold with Punctuated Evolution Foundation, a Stage 4 Building.

- Sterile have access to two extra population from population buildings (Eco Habitats, Cosmetic Genetics).

Lets compare it with a tier 0 planet (Atoll, Forest, Terran, Ocean):

- They have 3 more base population than Arctic, 4 more than Ice, 5 more than Barren, taking into account population buildings, they get 1 less than sterile, so would be 2, 3 and 4 pop difference.

- They get full benefit from Public-Private Partnerships: which is 20 flat science difference for being both fertile and temperate.

- Fertile planets get 4 extra pop with Punctuated Evolution Foundation, more than cold.

Boreal is the weird one in the middle, gets 6 science per population from Punctuated Evolution Foundation, being both Cold and Fertile, also 10 science from Public-Private Partnerships for the fertile tag.

Now comes the first layer of complexity:

- A planet could be from small to huge, affecting maximum population. The bigger the planet is, the less impactful is the relative population difference.

- All other resources are pretty important: you want food to keep growing population, you want industry to get the improvements faster. Dust while the least important is still desirable to not go bankrupt, specially until you get trade routes going as alternate income, that will take a while.

Lets see an example:

While barren has an impressive 16 science per pop, is just that, and 2 dust per pop, an Ocean has 10 less science per pop, but 8 food, 2 industry and 4 dust, also 4 more population. Medium barren with the population buildings would be 5 population, while ocean would be 9 population. Lets add all the buildings that affects them exclusively (not the ones and parts that affect everything):

you get 80 science on medium barren, plus 10 from Citizen Science (the cold part), plus 10 from Punctuated Evolution Foundation: that's 100 science.

Then on medium Ocean, is 54 science base, plus 20 from Public-Private Partnerships, plus 36 from Punctuated Evolution Foundation: that's 110 science.

What if both planets are huge? +2 pop on both: Barren gets 140 and Ocean gets 130, barren barely wins, but only if all you care is science output.

Then comes all the other complexities added on top:

- Many times you will place a slag and sludge center for extra luxury/strategic output instead, not to mention Citizen Science is behind a Stage 5 tech, its just 1 extra science until then (Exoscience Stations).

- Industry is king, while AI Labor gives a nice boost to industry, all cold planet systems are miserable to get going with their own industry. Fertile gets base industry, plus all the might from Xeno-Industrial Infrastructure.

- Food is essential to grow population over time, all cold planet systems are very slow to grow pops, even with external help with spaceports, you need to stay positive.

- You get approval hit with sterile planets, and more or a hit with the high science output ones, keeping good approval is important.

- Planets are not on isolation, you may get that extra helping hand with other planets to cover for food or manage system approval better.

- Having luxuries, strategics, or anomalies, or moons with extra pop, would affect the planet output and what bonuses you get from buildings.

- Then you have population specifics, faction specifics, maybe a constellation bonus, or quest rewards affecting output...

- Terraforming takes time and industry to get it done, and often time several steps to reach the goal.

TLDR:

- Don't overthink it, is way to complex on practice and there are too many variables. Both cold sterile and tier 0 planets have good science output.

- On a baseline: I like to have one or two tier 0 planets, to support all the other resources and approval, and maybe a large arctic, or a huge barren, also boreal are nice and easy to get from tundra or snow. But boreal only truly shines with Sophons and all their cold planet support.

- Then I go by gut-feeling more than precise analysis, taking all the above into light consideration, checking how the system is faring regarding all resources. I don't care enough to min-max to the extreme.

Lategame I make everything jungle or atoll.

Home system with 3 economic behemoth will out science produce the next 10 systems in your empire anyways. If were going late game with all upgrades, then gas planets out produce everything. The game isn't about capping production in a single system, its about reaching a win con before every other player.

But for factions not named Riftborn, Barren will out science produce oceans until you have the tech that transforms excess food too production, and building project that transforms productions output divided by 2 into science.

Ocean right, I knew I was forgetting something.
Yeah, ocean with the food conversion will general out produce theoretical bests but it’s endgame stuff.

I think the top priority is simply to go colonise systems that have the most planets because industry potential > science potential.

I would rather take a chance and settle a system with 5 cold planets, and fix the system later by terraforming and/or using particular governors ; than colonise a 1-2 planet system that will soon get limited no matter the bonuses it has or planet type.

Room to grow in your systems is essential because once the industry starts to seriously kick in, you will build in no-time all the science building that you would want.

Again, Industry is really the only top priority. And it helps science by letting you build Endless Research PArk and NTER faster. Everything gets build faster and it is the source of all power.