Value of Trade Items

[Marcusem78]

I was perusing a trade-related thread, and it made me think - is the value of trade items subjective? That is, is it based solely on the needs of the civ who wants it, or is it based on global supply?
For example, Civ A trades Clams to Civ B for Silk. Civ C trades Clams to Civ D for Dye, Crabs, and 2 gpt. Is it just because Civ D really needs a Health bonus? I recognize the inherent value on strategeic resources such as iron and horses in determining process as well.

[MoonWolf]

I'm not sure, but I think that the main factor is diplomatic points. The friendlier a civ is, the better deal you can make. Bur I've also noted some quite high demands for vital resources like iron, coal and oil (if receiver doesn't have it), especially in the late game

[McCrea]

"Everything is worth what it's purchaser will pay for it" -- Spock

[Blaupanzer]

Military techs and strategic techs are generally considered to be worth more by the AIs, probably to avoid exploits. This seems especially true when "Aggressive AI" is turned on. Not sure, as I never play without it anymore.

[Willem]

I generally don't see any difference in the trades between civs. If they have an extra health or happiness resource they usually do a straight swap. If they only have some gold, they almost always give me as much gold per turn as they have available at the time. Strategic resources are a bit different though, they're usually willing to give me much more for those, like another resouce or two plus all the GPT they can spare.

[rjmatsleepers]

Originally posted by Willem
I generally don't see any difference in the trades between civs. If they have an extra health or happiness resource they usually do a straight swap. If they only have some gold, they almost always give me as much gold per turn as they have available at the time. Strategic resources are a bit different though, they're usually willing to give me much more for those, like another resouce or two plus all the GPT they can spare.

My impression (very subjective) is that this was no longer true in BTS 3.13 - not sure about 3.17 because I haven't played enough yet. In 3.13, there seemed to be a cap of 3 gold for a "normal" trade, even when the AI had a lot more gold. There were exceptions - strategic resources such as iron, etc and for some reason things like hit singles. I recollect one case where the AI would only offer 3 gold for rice plus cow, but would offer 3 each if the trades were done individually. It is possible that the cap only applied when the AI was trading for a second example of a resource it already had, in which case it may have been fixed in 3.17.

RJM

[Blaupanzer]

I usually get offered whatever gold they have on a resouce from me. Selected resources put on offer can get ridiculous offers, based on their strategic value or the immediate need of the civ.

Going the other way, a resource is a resource, exchanged one for one, unless the AI resource is strategic. These are more expensive. Up to King level (I play almost exclusively on Prince, coming up with some really creative ways to lose), the AI does not seem to know when you are the one in desparate need.

The AIs will only offer resources you "need," but will trade even when furious.

[Supr49er]

The AIs always want my Horses, Iron/Copper, Oil and Uranium.

They seldom want Fur. I always have Fur - almost every game.

They seem to demand a high price for Stone/Marble.

[nbarclay]

In my experience, the AIs always want any resource they don't have. Always.

Under normal circumstances, resources that are solely health or happiness resources trade on a pone-for-one basis. Corporations can change the balance in two ways. First, buying the first resource of a type that is useful for a corporation tends to be more expensive than a straight one-for-one deal. But second, once you already have the first one, extras are a whole lot cheaper than one for one.

In addition to the impact of corporations, the 3.13 patch had a bug that resulted in some really weird deals. AIs were willing to trade for resources they already had and didn't have any use for more of. If they proposed a deal, it was one for one. But if a human proposed a deal, or tied to make a counteroffer, or tried to negotiate a renewal, the value the AIs were willing to offer was a whole lot lower.

Strategic resources have a higher value, with the exact relationship in values depending both on which strategic resource is involved and on the timing in the game. In particular, the early-game strategic resources seem to lose value in comparison with health and happiness resources as the game progresses. Note that ivory is a strategic resource for this purpose because it is a prerequisite for war elephants in addition to its happiness benefit.

I don't have a huge amount of experience with cash values of trades, but the general pattern is that the amount of gold per turn AIs have available to offer is almost never as much as they would be willing to pay for resources they actually need if they had more. The bug in 3.13 could result in extremely low prices (such as the three gold per cow rjmatsleepers reported) when the AI already had a resource but was willing to buy extras.