scoutsout said:
@WackenOpenAir: Would you be willing to expand on this topic, or perhaps offer a few examples? I'd really like to hear your perspective on this.
I always try to convert the value of resources into 1 comparable number.
The first 30-40 turns, i don't value anything but getting settlers out asap. This is done by an excel sheet. After that, when i have multiple cities and it is too complex to go by excel sheets, i will value something like this:
1 food = 3 shields = 12 commerce.
Of course, special situations like trying to get the slingshot could temporarilly change this. And overshoot and often many other things should be calculated for.
Later, when i am out of despotism, food and shields become pretty much equally valuable since the mines and irrigation are easilly exchangable.
1 food = 1 shields = 4 commerce.
Again, certain situations can change the convert rate. For example, leo's workshop can greatly increase the value of commerce.
Now, when you have a choise to build something, you can look at the return on investment of it. If you invest 100 shields on a marketplace that is gonna make you 12 gpt, i would say it returns 3 shields per turn and thus returns its investment in 33 turns.
Compare options like that try to find the ones that return their investments in the shortest amount of time.
You can also calculate this return on investment for something like an FP if you can calculate or properly estimate what the corrution reduction is gonna do for you. Or you can calculate the return on investment for a government change if you take the average anarchy period times your current production for the cost, and the per turn advantage after the change for the return.
Everything i do, i think about what will it return for me on the investment made.
It is of no use to make investments that do not pay back themselves within the expected game duration. It is also no good to make investments that pay back slower than other investments you could make.
The newby love for cathedrals is an example of this. It costs 160 shields i think. It returns 3 happy faces for the cost of 2 gold. Its net reward is 1 gold per turn or 1/4 shield per turn. It takes 640 turns to pay back for itself. With that wonder that makes it 6 happy faces, this would be reduced to 160 turns.
As you see, return on investment is something you don't always need to calculate. All experienced players know the cathedral sucks, they don't need prove. But it can help in other less extreme situations.
The devaluation thing is a difficult topic. I remember i once made some calculations on this in the sid level gotm. Lets see if i can find a link there.
http://forums.civfanatics.com/showpost.php?p=3501321&postcount=19
I haven't read it back now, but i remember i did some calculations in there and wrote them in the added word file. That should show an example of how i think about economy and civ choises in general.
I have always been thinking a bit about this subject, but never really got to a good way to put it to use in exact numbers. therefore, it is just a vague idea and all i can say is, x resources on turn 100 are worth more than the same amount of resources on turn 200.
Therefore, the calculated time to return your investments is not entirely correct, it is longer than what is calculated. If you give me 100 dollars today and i pay you back 10 dollars every year for 10 years long, you are not gonna be happy.
Another simple example of how to think about value, cost and reward:
It is turn 45, you have 5 cities now.
Your 5th city will grow to size 3 in 12 turns. If you start building a settler now, it will be ready in 10 turns. If you first build a warrior, your settler will be ready in 14 turns.
Building a warrior will cause no resources in this city to be lost. However, it will delay the settler by 2 turns and it will keep this city occupied for another 2 turns.
Delaying the settler by 2 turns costs you 2 turns of that cities entire production, that is at least: 4 food + 2 shields + 2 commerce, for a total converted value of 14.5 shields.
The cities shield production being occupied for 2 more turns may cost 4 shields for example.
So in this situation, building a warrior will cost you 18.5 shields. And thus, while many people fear the waste of 2 turns production when finishing the settler too early, building a warrior first makes it a very expensive warrior.
I have no calculations that prove my 1 food = 3 shields in early game though. This is something i decided for myself out of experience. I cannot back it up now. It should be possible to calculate a conversion rate between food and shields i think if you can enter the proper parameters into a formula, including the game length and production for each citizen (being different for the first ones that are in your productive capital that the late ones that will be in your corrupt ICS land)
That however is too much work for something i don't think is very usefull. I am happy with my 1:3 conversion rate for early game.
Later in the game, it is usually easier since as i said, food and shields are exchangable and the conversion to commerce isn't very hard to make (but it depends on how you spend your commerce)
If you look at it like this, you should also notice the immense cost of doing research. An early middle age tech costs 1200 beakers, this can easilly be converted in 300 or 400 shields depending if you use upgrading or cash rushing. So researching 3 technologies before you can build knights costs you like 1000 shields and thus 15 knights to begin with. This is numeric prove for the strength of "pointy stick" research.
Oh, and what i said "how it relates to the expected game length":
If your game is only gonna be a little longer than the expected time for the investment to pay back for itself, it is probably a bad investment. Due to the devaluation, the real time to repay is longer than the simply calculated one.
Also note that investments that do not help you reach your victory condition can often increase the expected game length. Removing certain investments will reduce the expected game length. Now it is key to choose the right investments so that you can go for the shortest game length.
For example, in an easy game, you may choose not to make the investment of researching past horseback riding and not making any investments in city improvements except the barracks. This may reduce the expected game length and allow you to win with just horses. If however you are not gonna be able to win with horses, you need to make investments for a longer game. These investments themselves increase your expected game length and if you didn't try with just horses, it may seem like that would have been completely impossible. The extra investments increased your game length so that you may not even take 25% of the world with horses before proceeding to knights.
This is what keeps the beginners who make many long term investments (city improvements) from daring to try and play without them. these investments increase their game length so that they may need cavalry to win the game and they just can't believe the game could be won by horses if they did not make all those investments.
)
although...i will take the chance if possible, early archer rush on one AI, and get my techs back courtesy of them. 
