I''m going to try to make a simple, galactic type trading game. I think I can handle everything except for the actual economic calculations. I''ve taken a general micro and macro economics course, so I have a vague idea of what I want to do, and an even vaguer idea of how to do it. On each world, there will be X number of Y industries. The cheap way would be for them just to blindly produce at max capacity. But I''d prefer to have the industries of a world stop producing at a specific price. So, basically, I''d like each world to have a supply curve. Likewise, each world should have a demand curve. And the price of goods would be the intersection of these two curves. This would be too hard to do, I would just need to solve a simple linear intersection problem. The hard part is in figuring out what these lines should be. On an urban world, where there are no farms, the price of food should be much higher, and many more units of food demanded. But what kind of slope should this demand curve have? I need some semi-realistic way of assigning atleast two points of both the supply and demand curves for each world, from which I can derive a linear fit, and from that I can figure out equilibrium pricing. I''m afraid this is as far as my economic understanding goes. If anyone knows how economic type games determine pricing, I could use that too. Any thoughts are appreciated. Thnx

Okay, seeing as how no one has responded to this thread, I''ll put it another two cents.

I think it''s possible to exact one point where there is no supply. For this pretend case, we''ll assume it''s food.

If there is _no_ food to be had, the price for the first unit offered will be whatever the richest person in that market can afford.

So, assuming we are on an afluent, urban world, and there is no food to be had, and everyone is desperate for some food, one unit sold will be the amount of money the richest person has.

If two units are sold, the price will be however much the second richest person has, (ssuming several factors of course)

On the other end, if there is an infinite supply of food and no transportation costs, the price will be zero.

This gives three points, to which a cubic spline, or a quadratic spline, or a best fit linear graph, can be constructed, which will give the demand curve.

Now, the supply curve...
The most obvious case would be when the price of food is infinite (namely, when there is no food to be had, and one unit of food will go for whoever much anyone can afford). At this point, supply produced (on the planet) would be equal to it''s max capacity, which is, of course, a function of the number of food producing industries on the planet.

Supposing that the cost of food is zero, (on the supply end. Transportation costs would exist, of course, but those aren''t important to the supply curve) then no farmers would produce any food. That gives us a second point.

This would give a rough approximation of the supply curve. (Rough, because of its linearity).

This, of course, is a simple model, that doesn''t take into account factors in food production, such as cost of other items (say, growing cotton), and this model wouldn''t necessarily reflect cost of intermediate goods (like metals, and cotton), but it''s all I have so far.

If anyone has any thoughts, I''d appreciate it. Even if you don''t really understand economics or what I''ve been talking about, just having somebody to bounce ideas off of is helpful.

Thanks for your time

Here''s a link y''might consider.

http://www.econs.ecel.uwa.edu.au/235/IIT/foundations.html

That''s a pretty good link, I had forgotten some of the stuff (okay, that economics course was a while ago). It''ll take me a while (probably after finals) to go through it all.

I guess my best bet is to assign utility values to all the items, and base demand from that...

I know this kind of game seems to be rare, but if anyone has a link to an economic game and its source code that I could look at, that''d be great. I could spend several months and reinvent the wheel, but I''d rather just go to the used car lot, get a lemon, and tweak it

I''d be very careful about overthinking this, unless you''re in it just to have some fun with modeling and numbers. In that case, ignore me.

If you''re trying to make a game, though, take care to consider gameplay first. Why? Because if you dream up and code a sophistocated model without concerning yourself with defining the bounds of acceptable and enjoyable gameplay, in terms of how the player can make choices, what strategic tradeoffs there are, etc, etc., you''ll have more of a possibility of running into places where the model works but the gameplay doesn''t. By all means, apply your economic knowledge, but I wouldn''t put too much effort into fidelity.

Brad Wardell, the author of The Corporate Machine, a popular corporate sim, says that alot of the AI and works underneath the hood are game designer hocus pocus rather than academically faithful economic modelling. He simply tweaks things to get them right and get the right feel.

Keep in mind also that not only will you have to understand a complicated model, you''ll have to understand it so well that you can maximize it and predict outcomes amongst various players. If you have AI, you''ll have to understand it well enough to teach the machine to play at varying difficultly levels.


In your posts I noticed that you were playing with ideas like raw goods and intermediary items (and possibly intermediary production costs, such as factories or refineries?) Personally, I think this is of limited value unless you''re going to allow players to deal with or modify these factors. If they are inert and unchangable, then they''re really just modifiers, and you could achieve the same ends with your own SWAG (Simple Wild A** Guess) approach. For instance, you could have a factor, such as "unified labor market" which drives the cost of manufacturing up on one world, or "political instability" which randomizes prices.

I don''t mean to dissuade you, but only to encourage you to think first of the gameplay. From there, simple and appropriate models will arise to meet the needs of play, rather than the needs of an economic model most of your players probably won''t understand.

Consider checking out X2: The Threat for their economic model. They have a very straightforward, easy to understand approach while allows players not only to be traders but manufacturers of goods, and you can influence entire local economies. You might get some ideas from the fansites. Good luck!


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Just waiting for the mothership...