What exactly does the Commercial trait do?

[morchuflex]

Hello.

What exactly does the commercial trait do (with C3C 1.22)?
Info on this topic is contradictory, and the civilopedia is a joke.
IIRC, it seems that
a) city central tiles produce one more gold, but only for towns and metros (pop > 6), and
b) the OCN is increased by 25%.
Is that all? If this is the case, it means that COM does absolutely nothing for you during the first 100 turns or so (until at least some cities grow beyond 6 and you hit what would be the OCN limit for civs missing this trait), does it?

However, I've read (from a usually reliable source) that all COM cities benefit from reduced corruption, no matter the number of cities, as if they had a CH from day one. Could this be true?

 

[Tomoyo]

Metros get three extra. However, the 25% increase in OCN means about 25% more productivity... I like commercial because it start with Alphabet. You can't underestimate the power of starting with alphabet.

 

[Pirate]

Do you get cheap marketplaces and banks?

 

[Theoden]

No, commercial has no discounts on buildings.

 

[morchuflex]

The 25% increase in OCN means about 25% more productivity.

That's dubious. As I understand it, it doesn't means that you have 25% less corruption in every city, but that you can build 25% more cities before you hit the "increased corruption" limit. Therefore, only those cities that would be beyond the OCN of a non-COM civ benefit from this increase. Core cities, the most productive ones, won't benefit from this advantage.
Am I wrong?
As for the extra gold from center tiles: the +1 gpt is nice, but SEA civs get it from day one on all coastal cities. And the 3 extra gold for metros sounds great, but is not even worth the extra shield that industrious metros enjoy (since 1 s = 4 g).
What do you think?

 

[Theoden]

The OCN increase will help your cities even if they are not beyond the OCN yet. Being beyond OCN just means that rank corruption starts to get really bad. For a more detailed and comprehensive explanation look here

 

[Tomoyo]

The OCN increase will help your cities even if they are not beyond the OCN yet. Being beyond OCN just means that rank corruption starts to get really bad. For a more detailed and comprehensive explanation look here

You really did something to mess up that link...

 

[Theoden]

It should be fixed now

 

[morchuflex]

I'm already familiar with Alexman's article. The trouble is, I suck at maths. I just can't sort out formulas (I teach literature for a living). So, words would be welcome.

 

[Doc Tsiolkovski]

IMHO there isn't that much to say about COM. The extra commerce is nice, but hardly noticable before a time when you have Banks everywhere, and tourist bonus easily outshines it. SEA is clearly superior here.
Starting with Alpha is great; SEA gets that as well.

The reduced corruption...until Monarch, you'll hardly notice it with your usual empire of 20 cities, and some corrupt colonies. Emperor, it is helpful for big empires.
From DG, with only 70% optimal cities, it begins to shine - and for Sid, it is easily the most powerful trait. 50% optimal cities .
So, the usefulness solely depends on the level. I'm an absolute fan of COM, but I wouldn't seriously call it very powerful (at least, compared to SEA) for Monarch and below.

 

[microbe]

This is why Hitties are often so powerful (they are EXP and COM right?)

 

[SJ Frank]

That's dubious. As I understand it, it doesn't means that you have 25% less corruption in every city, but that you can build 25% more cities before you hit the "increased corruption" limit. Therefore, only those cities that would be beyond the OCN of a non-COM civ benefit from this increase. Core cities, the most productive ones, won't benefit from this advantage.
Am I wrong?

You know, I used to think that Rank-Corruption does not matter until you build to OCN-th city, until I re-read Alexman's article more closely.

The article basically says that, when dealing with rank-based corruption, and assume that there is no multiplier at all (playing at regent, monarchy government, no FP, etc), the OCN-th city would receives 50% corruption from Rank-Corruption.

For example, if the OCN for the map is 20, then the 20th ranked city would have 50% rank-corruption.

Also, if the city's rank is 50% of the OCN (the 10th city when the OCN is 20), then it has 50% * 0.5 = 25% rank-corruption; if the city's rank is 30% of the OCN, then it has 30% * 0.5 = * 15% rank-corruption. Basically, find the city's rank as a percentage of the OCN, and divide it by 2, and that's your corruption

And rank-based corruption start taking effect with the 2nd city that you build, though it would be fairly minimal in the beginning.

Now, there are numerous ways to increase that OCN number, such as being commercial, being Republic, build the FP, etc, and there are some ways to decrease the OCN, like playing at higher difficulty.

Commercial does increase the OCN number by 25%. However, since Commercial does not affect distance-based corruption at all, and its 25% bonus is not multiplied, but added to some of the other bonus, it does not translate to 25% the overall production increase of your civ. The real number is probably around 8-10% or so, just by looking at the numbers.

 

[morchuflex]

Well, I've just done some interesting comparative testing.

I took 2 different starts, one with a non-COM civ (Zulus), the other with a COM civ (Greeks).
In each case, I built 3 additionnal cities at distances 3, 6 and 12 from the capital.
I played until each city reached pop 6 and roaded all adjacent tiles.
Then, I ran a corruption comparison.

Zulus: at distance 3, one corrupted gold appears when total gold reaches 8.
At distance 6, one corrupt when total 4, and 2 when total 11.
At distance 12, one corrupt when total 2, 2 when total 6 and 3 when total 10.

Greeks: well... exactly the same numbers!
Except for distance 6: the 2nd corrupted gold appears when total reaches 12, not 11.

Seems pretty marginal to me.
Edit: of course, I admit the test was short (I'm lazy). But at least it shows that COM does little to help you during the most crucial phase, the first 100 turns.

 

[Doc Tsiolkovski]

Well...if you then have a look at Sid, where OCN is only 50% .
So, for map-size OCN (=Regent) 20, your 10th city will be 50% corrupt. Easy to see that even a reduction to 40% will be noticable.
Also, the FP (and SPHQ) are doubles/tripples the OCN. And since the OCN for COM is increased, that effect is also multiplied.
For Regent, the FP won't mean 2x 20 + (25% of 20), but 2x (125% of 20). 50, not 45.
And, the gpt saved is naturally higher in a trade-bonus Gov.

 

[nullspace]

Well, that's because the commercial trait affects RANK corruption, not DISTANCE corruption. In your test, you have only 4 cities, so the rank is very low for all of them, even though the distance is high. In a normal game, even second-ring cities will have a rank around 6-12, and you only tested rank 1-3. I bet if you did a test like that, you'd see a real difference.

Bottom line, the commercial trait does what it's supposed to: gives extra commerce in large cities, and reduces corruption in large empires. Saying that it doesn't help much in the early going is valid criticism, but I think the lowered corruption (and waste) is a big effect for even medium-sized empires.

 

[Tomoyo]

No one responded to my saying that start with alphabet was one of the strengths? DocT, I would have thought you would have...

 

[IbnSina]

Starting with Alpha is great; SEA gets that as well.

It is great. He did respond...

 

[Tomoyo]

...oops, I missed the first post...

 

[morchuflex]

@SJ Frank:

Thanks for the detailed information. If you're right, COM should start to shine for large empires on Emperor+. Emperor is precisely my choice difficulty level. So, I'll investigate more closely.

I agree my test was too short.
If I have spare time, I'll run a larger test with at least 20 cities.

 

[gunkulator]

For Emperor+, I rank commercial as the second best trait, after agricultural of course. Makes the com/agr Iroquios the most powerful civ IMHO even without their killer UU. In fact in my last Iroquios game, I didn't even have any horses at all until well into the Middle Ages and I still dominated. Having more uncorrupt cities that also happen to be larger than your opponents is just an awesome combo.