作者：trac.bookofhook

游戏世界的虚拟经济总是成为设计师之间激烈讨论的主题。很多人认为游戏的经济是很容易设计的，只要在行的人稍微花点心思，设计出“完美的”经济就会像一部加满油的机器，可以持续运转下去。这种经济中的点点滴滴都是设计师定义的，对吧？（请点击此处阅读本文第2、3篇）

错。

设计或调整虚拟经济都是困难的，并且是非常，非常困难的，因为起作用的变量太多了，微调任何一个都可能严重影响其他变量。因此，我决定写一系列文章来专门介绍游戏经济的基础知识。本系列的目的不在于教大家“如何设计虚拟经济”，而更像是对“在游戏经济中的起作用的因素”的调查—-目的在于，在思考如何解决问题以前先理解问题是什么。

我们理所当然地认为游戏世界有一些标准的货币，如金币、积分或金钱。但通过把商品和服务转化为货币然后把货币转化为商品和服务，我们可以提供一个方便的媒介，促进玩家间简单的交易。这是一个理想化的系统，只有在理想化的游戏世界中才存在。

但在我们更加深入地思考货币以前，我们先认识一个没有货币的简单系统，然后在里面加入货币形成经济，看看会发生什么事。

没有货币的经济

没有货币的经济可能是一种令人困惑的情况。比如，当张三想从李四处获得某物，他必须拿出等价的东西作为交换。不仅李四必须认为张三的东西是自己想要的，而且这个东西必须具有合适的数量，这样才是等价交换。物物交换系统不能很好地解决小部分价值不等的问题（因为你不能找零）。

李四做了一个很好的钢盔。张三正准备把他破旧的铜盔换掉。在最糟糕的情况下（对张三而言），张三手上没有任何令李四感兴趣的东西—-李四想要一匹马，而张三没有马。张三可能有价值相当于一匹马的东西，但仍然不能完成交易，除非他可以说服李四接受“间接的马”或除非他把自己的东西换成一匹马后再来找李四换钢盔。

假设张三的东西是一个珍贵的卷轴，而王五很乐意拿自己的马交换东西。但不幸的（或者说这通常就是现实情况）是，有马的王五需要的是两只羊，而赵六有羊，但他想换灯；李七有灯，但他想要钢匕首；陈八有钢匕首，但他想要……在现实社会中，这种交易会变得非常复杂，绝不是个人之间就能处理好的。所以，出现了负责这些中间环节的“经纪人”，当然，他们要从交易额中拿走一小部分作为自己处理这些经济摩擦的报酬。

我们把这个情境简化一下：假设张三确实有马。但事实上钢盔只值半匹马—-那么李四可以交换吗？他可以做更多钢盔，但张三只需要一顶钢盔，或者李四可以花张三认为等价于马的100金币直接买下马，然后张三再拿出这笔钱的一半返过来找李四购买钢盔。在这次交易中，我们借用了具有相对等价的物品。

这里有两有大问题：寻找等价物和做交易。二者都可以被标准化的货币系统解决。李四可以在他的钢盔上再贴50金币给张三换他的马，或者他可以直接拿出100金币买下马，然后张三再拿出这些金币的一半买钢盔，剩下的50金币放自己口袋里。他们甚至可以通过一个中介（市场）来完成交易，而不是两人直接做交易。显然，这比单纯的物物交换经济更加高效。

然而，为了让货币生效，必须有诸如银行、宗教或政府等权威机构的支持。如果这个权威者不想介入其中，怎么办？如果开发者说“我知道如果我做了一个经济系统，我会搞砸它，所以怎么办？”

正如我们所见，单纯的物物交换系统运作得并不好。但人是非常精明的，所以单纯的物物交换经济很快就被实际上的货币经济取代了，因为人们希望优化市场交易活动。在人类历史上，牲畜可能是以畜牧为生的文明最早使用的一种货币。

不幸的是，奶牛很难用于小价值交换，因为不可能把活生生的奶牛分成几个部分（游戏邦注：否则就无法实现它的非食物功能—-产奶）。如果你想从农夫手中购买一磅的苹果，你不可能给他一整头奶牛，但你也不想要相当于一头奶牛那么多的苹果。

所以，缩小货币成为必要的一步，这样才有可能进行小价值交易。这种小货币仍然有内在价值，但现在我们先看看盐、鹿皮、小块金属、咖啡豆或烟叶。在虚拟世界，通用形式的货币几乎总是一种具有普遍价值且可替代的东西。如果游戏支持锻造或木工，那么货币单位可能是一粒铁砂或一个木片，因为这些原材料（相对地）容易交换具有相对等价的东西，如武器和工具。

这种事实上的货币本身除了自己作为原材料的价值，没有其他任何特殊价值支撑它成为通用货币。在现实世界中，这并不是特别有效的经济系统，因为篡改和诈骗（假冒、短斤少两，等等），但在游戏世界，它却是一种稳定的系统，因为游戏世界的物理不支持这些技俩（很不幸，除了常见的货币漏洞）。

为了让这种货币存在下去，设计师必须在游戏中加入一些可以携带的且具有不可争议的价值的物品。如果没有这种物品，那么这个游戏的经济就仍然是一个物物交换系统。

抽象货币的出现

随身携带一些原材料以便换一杯茶，似乎有点极端了。所以下一场货币革命是抽象货币的诞生—-由公认的机构发行代表一定量固定价值的票据。张三有500磅的铁砂，但他不想随身带着它们。所以他把铁砂交给当地的银行，换到代表他所拥有的铁砂的票据，持票人可凭票换铁砂。张三遇到李四，说“我给你20磅铁砂换你做的钢盔”，李四同意了。张三拿出相当于20磅铁砂的票据，李四确认是有效的票据后，很高兴地交换了。

这样，能代表有形价值的纸币就诞生了。

但游戏经济需要这种程度的标准化吗？很难说，因为纸币解决的（和遇到的）真正问题并不存在于游戏世界。玩家通常可以安全地携带或储存他们的有形资产（除了系统滥用和漏洞），在构建一个固定的货币系统中，没有一个中心的游戏实体具有既得权益。

标准化货币

玩家希望游戏中的货币标准化。他们想要积分、金币、钞票，等等。玩家希望理解物品的相对价值，最好是通过在商店里看到的那种标价。他们不想计算多少盐能换多少狼皮。

但这是一个便利性的问题，而不是一个功能性的问题。标准化货币便于交流和理解，但仅此而已（我没有贬低这两种属性的意思，但便利性和功能性之间存在相当大的差别）。

因此，游戏开发者认为标准化货币仍然是需要的，所以他们打算创造一个出来，这比你想象的来得棘手。

设计师必须让玩家关心这些货币。或者说，这些货币能用来购买什么？如果所有怪物都掉落金币，但这些金币不可能转化成可触的实用物品，那么它们的价值就不会太大。标准化货币必须提供真正的价值。

这种价值可以表现为通过严格的货币交易（货币从玩家手中回到系统的转移）而获得的商品或服务。这些商品和服务（“货币的稳定剂”）提供了两个重要的功能：第一，它们代表了货币的真正价值（主要目的）；第二，它们把钱从系统中抽出来、抵消通货鼓胀。

然而，为了有效，这些货币稳定剂必须具有普遍的价值或必要性；它们必须衡量财富，代价必须是循环的。

只对小部分人必须的东西不能成为货币稳定剂—-当与需要这些东西的玩家交易时，它们在这些核心人群之外的作用绝对是间接代价的结果。具有固定标价的商品和服务对于无力购买它们的人来说具有很大的影响，而对富有的玩家来说则是微不足道的，所以它们稳定货币系统的作用是比较弱的。最后，一次性购买的商品和服务，无论有多昂贵，都是相对差的货币稳定剂，因为它们只能影响玩家一次，之后就越来越不重要了。

一个用于解决这些问题的常见稳定剂是“租用”，也就是你支付相当于某物品的价值/效力的费用，以换取该物品的使用权。表面上看这是一种吸引人的办法，但实际上，这种办法只能局部适用。如果你把费用定得太低，所有人争先恐后地花钱租东西—-游戏将会从娱乐变成工作；如果你把费用定得太高，那么人们就不会考虑租东西，这样钱就贬值了。物品使用、损坏和修复造成的费用是类似的，武器和盔甲磨损，必须花相当于物品价值的成本来修复。这其实是换了马甲的“租用”。

基本上，标准化货币是可行的，但它的真正价值直接取决于可以购买的服务和商品。如果在游戏经济中，任何可以购买的服务或商品都是可以免费获得的（即由怪物掉落或玩家技能产生），那么标准化货币就没有价值了。游戏经济的另一个极端情况是，货币价值极大，因为所有重要的道具和服务都只能通过货币交易来获得—-事实上，这种系统具有垄断性质。

通货膨胀和货币

什么是通货膨胀？简单地说就是“钱太多，货太少”，这句话经常出现在金融和经济讨论中。虽然这么说是合理的，但在分析复杂经济中的通货膨胀时，这句话就太简单了。

在没有任何货币的社会中，无所谓有没有通货膨胀。在物物交换经济中，关键物品如牲畜或农产品的突然短缺会导致“物价上张”。比如说，你是铁匠，本来你需要花一个马蹄铁就能换到一只鸡，通货膨胀后你就需要五个马蹄铁了，但同时，想换你的马蹄铁的人（你的消费者）也需要拿五倍的交换物出来。你必须把成本转移到你的消费者身上，这是传统的通货膨胀驱动器之一。

相反地，当商品供过于求时，鸡泛滥了—-你可能不会向农夫买鸡了，因为你在自己铁匠铺附近就能抓到鸡。这种供过于求导致商品的相对价格下降。

所以，供应和需求同等地影响通货膨胀，无论标准化货币是否存在。

然而，标准化货币的引入可能使情况更复杂了，因为你现在手上有的是一种媒介物，它所代表的价值可能是等价的，也可能是不等价的。定义上说，一只鸡值一只鸡，但写着“一美元”的纸钞到底具有多少价值？价值的间接性大大增加了系统的复杂性。

如果上述货币其实是没有价值的，也就是“并不值它所代表的价”，那么物价就上涨了，即使商品的相对供求是稳定的—-如果一美元是没有价值的，那么即使你给我一大捆美元，它们对我来说也仍然没有价值。0乘以无穷大仍然是0。

换句话说：通货膨胀并不是直接由系统中有太多钱导致的。通货膨胀在没有钱的情况下仍然可以存在；当货币供应量有限或逐级减少时，如果缺口足够大，仍然会产生通货膨胀。

对普遍的观点相反，游戏中出现通货膨胀的最常见原因，并不是怪物一直掉金币，而是钱直接转变成过剩的商品（通过金币交换商品）。如果掉落的钱是假币，假币不可能转化成任何价值，那么它们就是毫无价值的—-这样你又回到物物交换经济了。

所以，说到底，货币过多（怪物直接掉落的）只是一种商品过剩的间接形式，这就是为什么商品膨胀和货币膨胀其实是同一回事。

显然，货币过多可以转变成商品过多，进而变成通货膨胀。类似地，如果商品或服务可以通过其他形廉价或免费地获得，那么货币就会贬值。

这意味着无论是掉落物品还是“免费”玩家产生的商品或服务在通货膨胀中都有显著的作用。例如，如果所有小镇都有一个NPC向玩家收取去往其他小镇的费用，而其他小镇里的服务只能通过真钱购买获得，这就通过这个系统增加了货币的边际价值。但如果你使玩家自己可以传送，那么你就只是通过增加之前只能通过货币交易获得的服务的供应，对通货膨胀产生微小的影响。甚至更糟，你现在降低了货币的整体价值，因为只有一种服务是通过货币交易获得的。

缓解恶性循环的通货膨胀的办法是有的，但我想留到之后的文章中。现在，我只想告诉大家，通货膨胀的真相不只是关于物品掉落或金钱掉落，还与供需之间复杂的交互作用有关，任何一点小小的变化都可能对虚拟世界的经济产生重大影响。

总结

标准化货币，无论是官方认定的还是事实上的，在交易中起到润滑剂的作用—-使所有参与者之间的交易过程更高效、更便利。只有当玩家认为货币有价值，它才有价值。这意味着货币本身必须具有内在价值（铁砂）或者货币必须能换取其他有价值的东西（比如，只能从NPC商人处获得的商品和服务）。

游戏世界在没有官方货币的情况下仍然能正常运作，只要有些事实上的、具有普遍价值且供应有限的货币存在，但这很大程度上取决于自然行为的偶然发生和预期。

（本文为游戏邦/gamerboom.com编译，拒绝任何不保留版权的转载，如需转载请联系：游戏邦）

The Design of Online Economies

by trac.bookofhook

Part 1: The Role of Currency

The virtual economies of online persistent games are always good fodder for message board arguments and backseat designers. Everyone thinks that it’s an easy job, and that if someone was just competent and put a little thought into it, a “perfect” economy could be made and left alone like a well oiled machine. Hell, everything that’s in that economy is defined by the designers, it must be easy, right?

Wrong.

Designing or even moderating virtual economies is hard. It’s very, very hard, because there are so many different variables at play that tweaking one may have rampant effects on others. For that reason, I’ve decided to write a series of articles (hopefully) about the basics of online economies. This is not intended to be a “how to design virtual economies” series, but more of a survey on “factors at play in online economies” — an attempt to understand the problem before even thinking about solving it.

It’s taken for granted that an online game will have some kind of standardized currency such as gold pieces, credits, or dollars. By converting goods and services to currency and then back again we can provide a handy intermediary facilitates easy trade between players. This is the idealized system, and in a perfect world it works.

But before we think too much about currency, let’s first look at a simpler system that has no currency and then see what happens when we add currency to an economy.

An Economy Sans Currency

An economy that does not have currency can be a confusing environment. When Alex wants something from Beliza, he must have something she values equally. Not only must Alex have something that Beliza values, but he must have something in the right amount so that it is an equal exchange. Barter systems don’t support fractional values very well (i.e. you can’t make change).

Beliza has a nifty steel helm she’s made. Alex could really use an upgrade from his old, battered bronze helmet. In the worst case (for Alex), he has nothing that Beliza is interested in — she wants a horse, and Alex doesn’t have a horse, so that’s that. Alex might have something worth one horse, but he’s still out of luck unless he can convince Beliza to accept “one horse by indirection” or unless he undertakes the work to convert his valuables into one horse.

For example, he might have a valuable scroll that Xavier would gladly trade for one of the horses from his stable. To make matters worse — and more realistic — what he’ll find is that Xavier has horses, but wants two sheep, and Saul has the sheep, and wants a golden lamp, and Thomas has a golden lamp, but wants a steel dagger, and Chuck has a dagger, but wants…etc. etc. In a complex enough society, this can become so cumbersome that it’s unworkable for individuals so you see the rise of a dedicated “market maker” class that handles all the indirection and skims a little off the top — profiting through economic friction.

Let’s take an easier situation, where Alex actually has the horse. But realistically, a steel helm is only worth about half a horse — so how does Beliza make change? She can make more helms, but Alex might not need more helms. Or she can look for other items that Alex finds useful to make up for it, but then we’re back to trying to find items of equal relative value.

There are two major problems here: finding items of equal value and making change. A standardized currency system can solve both of these problems. Beliza can trade her helmet plus 50 gold pieces to Alex for his horse, or she can just buy the horse outright for 100 gold pieces and Alex in turn can take the cash and buy a steel helmet and pocket the rest. They can even perform this exchange through an intermediary (a marketplace) without ever dealing with each other directly. Obviously, this is a much more efficient system than a pure barter economy.

For a currency to work, however, it requires the backing of an authoritative instituion such as a bank, religion or government. What if the authority figure doesn’t want to get involved? What if the developer says, instead, “Hey, I know if I make a currency, I’ll screw it up, so just deal with it”?

As we’ve seen, a pure barter system just doesn’t scale well. But humans are pretty crafty and resourceful, so pure barter economies rapidly produce de facto currencies as humans attempt to optimize marketplace transactions. In human history, livestock is most likely the original currency in those cultures with domesticable animals.

Unfortunately, cows are pretty unwieldy for smaller payments because they don’t fractionalize very well (without making a mess and ruining its non-food utility). If you want a pound of apples from the farmer, you’re not going to give him a whole cow for them, but you may not want one whole cow’s worth of apples.

The next step then is to reduce the size of the currency so that smaller payments are feasible. This smaller currency will still have intrinsic value, but now we might be looking at salt, deer skin, small pieces of metal, coffee beans, or tobacco leaves. In a virtual world the common form of currency that arises will almost always be something of universal value and that is fungible. If a game supports smithing or woodworking, the unit of currency may be a piece of iron ore or wood, since these are raw materials (relatively) easy to convert to items of real value such as weapons and tools.

This de facto currency itself is not backed by anything of particular value other than its own raw materials. In the real world this is not a particularly robust system because of manipulation and fraud (counterfeiting, “shaving”, etc.), but in an online world it is a stable system simply because the world’s physics prevent exploitation (excepting the unfortunately common occurrence of bugs).

For such a currency to develop the designers must provide some type of in-game item of the appropriate portability and uncontested value. If they fail in this regard, then a pure barter system remain.

The Rise of Abstract Currencies

Now carrying around a few dozen pounds of base materials just so you can get a cup of tea seems a little extreme, so our next evolutionary step is the creation of abstract currencies, where accepted institutions write notes worth some fixed sum of currency. Alex has five hundred pounds of iron ore, but he doesn’t want to lug it around with him everywhere. So he goes to his local bank, gives them the ore, and in exchange they issue him a note for any amount of ore he wants, redeemable by the note’s bearer. Alex runs into Beliza and says “I’ll give you twenty pounds of iron ore for that steel helm”, which she gladly agrees to. He proffers a twenty pound note, and Beliza — recognizing the validity of the note and the reputation of its issuer — gladly makes the exchange.

And thus we have the rise of paper currencies backed by something of tangible value.

But do online economies need this level of standardization? That’s a tough to say, because the real problems that paper currencies solved (and suffered from) don’t really exist in online worlds. Players can usually carry or store their valuables safely (modulo system exploits and bugs), and there is no central in-game entity that has a vested interest in establishing a fixed currency.

Standardized Currencies

Players expect standardized currencies in their online worlds. They want credits, gold pieces, pounds, dollars, etc. They want to enter the world understanding the relative value of things, ideally established by prices they see in some store. They don’t want to sit down and try to figure out how many pounds of salt a wolf pelt is worth.

But this is a convenience issue, not a mechanical one. It aids communication and understanding, but that’s it (not to devalue those two attributes, but there is a fairly large difference between convenience and functionality).

For this reason the game’s developers may decide that a standardize currency is still required, so now they’re put in the position of creating one, which is trickier than you’d think.

The designer must make the player care about the currency. What does it buy them, literally? If every monster drops gold pieces but those coins can’t be converted into something tangibly useful, well, it’s not going to be worth too much. A standard currency must provide real value.

Such value can be provided in the form of goods or services acquired strictly through currency exchange (the transfer of currency from players back into the system). These goods and services (“monetary stabilizers”) provide two important functions: first, they establish a real value for the currency (their primary purpose) and second, they pull money out of the system, offsetting inflation.

However, to be effective these monetary stabilizers must be universally valuable or necessary; they must scale with character wealth; and the costs must be recurring.

Items that are only necessary for a subset of players are ineffective monetary stabilizers — their effect outside that core group is strictly the result of indirect costs when interacting with players that need those items. Goods and service that are at a fixed price have an over large effect on players that cannot afford the item, and a negligible impact on wealthy players, and thus their ability to stabilize a monetary system is relatively weak. Finally, goods and services that are purchased a single time, no matter how expensive, are relatively poor monetary stabilizers since they affect each player only once and then cease to be relevant.

One common stabilizer that tries to address these concerns is “rent”, where you lose items if you do not pay some fee proportional to the value/power of your items before logging out. While appealing on the surface, in practice this technique is only partially successful. If you make the tax too exorbitant, everyone ends up scurrying for cash to pay rent — and then the game moves from entertainment to work. If you make the tax too light, then people don’t think about it and, again, money is devalued. Item wear, tear and repair is a similar taxation, where weapons and armor get damaged and must be repaired at a cost proportional to the value of the item. This is just “rent” dressed in different clothing.

Ultimately a standardized currency is feasible, but its true worth depends directly on the services and items that can be purchased. In an economy where any service or item that can be bought is also available for free (eg. dropped by monsters or as a player skill), then standardized currency is worthless. At the other extreme is an economy where currency is extremely valuable since all important items and services are available solely through currency exchange — in effect, the system has a monopoly.

Inflation and Currency

The simple description of inflation is “too much money chasing too few goods”, a common quote you’ll find in many banking and economic discussions. While a reasonable summation, it’s far too simplistic for any real analysis of inflation in any complex economy (including virtual ones).

For starters, it is trivial to envision inflation in a society that lacks any currency. In a barter economy a sudden shortage in a key product such as livestock or produce will drive all “prices” higher. If a chicken used to cost you, a blacksmith, one horseshoe, and now it costs you five horseshoes, then you’re going to find that you’ll charge your own customers roughly five time as much for one horseshoe. You have to pass the costs on to your customers, which is one of the classic inflationary drivers.

Conversely, when there is a glut — say, a chicken invasion — then Farmer Dave may not get anything for one chicken since you can just grab one running around your smithy. This time over supply has driven the relative price of a commodity downwards.

So supply and demand affect inflation equally, irrespective of the presence of a standardized currency.

However, the introduction of a standardize currency can complicate things, since you now have an intermediate representation of worth that may or may not have actual value. A chicken is worth one chicken, by definition, but what, exactly, is a note inscribed with the phrase “one dollar” worth? This indirection of value can have significant repercussions to the complexity of a system.

If the currency in question is effectively worthless, literally “not worth the paper it’s printed on”, then you’ll have price inflation even if the relative supply and demand of goods is stable — if a dollar is worthless, you can bring me a barrel full of dollars and I still won’t find it any more valuable. Zero times infinity is still zero.

In other words: inflation is not the direct result of too much money in the system. Inflation can exist without money, and inflation can still exist when there is a limited or even diminishing money supply if scarcity is great enough.

Contrary to popular belief, the most common reason for inflation in an online adventure oriented economy isn’t due to monsters dropping money all the time, it’s because that money translates directly into an overabundance of goods (through the exchange of coins for goods). If loot drops were strictly coinage, and that coinage could not be transformed into anything of value, then it literally would be worthless and irrelevant and you’re back to a pure barter economy again.

So in the end, an oversupply of money (from constant loot drops from monsters) is just an indirect form of an oversupply of goods, which is why item inflation and monetary inflation are effectively the same thing.

Obviously, an excess of money that can be transformed into an excess of goods will cause inflation. Likewise, if goods or services are available inexpensively or for free through other means then money loses value.

This means that both looted items and “free” player generated goods or services will affect inflation dramatically. For example, if every town has an NPC that for a nominal fee will “bind” you to that town, then there is a valuable service available that only money can buy — by extension, this increases the marginal value of currency throughout the system. But if you give that ability to some players, then you have just caused a slight bump in inflation by increasing the supply of a service heretofore only available through currency exchange. Even worse, you’ve now dropped the value of the currency in general since there is one less service exclusive to currency exchange.

There are ways to reduce the inflationary spiral, which I will discuss in a later article, but for now I really wanted to illuminate the fact that inflation is not just about item drops or looted money, it’s about the complex interaction between supply and demand, and how small changes can have large effects on a virtual world’s economies.

Summary

Standardized currencies, either official or de facto, provide economic lubrication — transactions happen more efficiently and with less overhead and strain for all participants. A currency is only as valuable as players believe it is, which means that the currency itself must possess inherent value (iron ore) or the currency must be backed by something valuable (e.g. goods and services only available from NPC merchants).

A game world can function just fine without an official currency so long as some de facto currency of global economic value and limited supply establishes itself, but this leaves a great deal up to chance and an expectation of emergent behaviour.(source:trac.bookofhook)