Path of Exile’s economy is the most important element of the game to us. It’s why we designed it to be played exclusively online. We examined the economies of other online RPGs and looked at how players interacted with each other in trade. In order to make gold a viable currency, the developers created many artificial sinks that do not have any real gameplay benefit. In some games, rather than using these built-in gold systems, players seem to prefer to barter item-for-item, inventing their own currencies and relative values. This development diary entry describes how we used these lessons to design the trade systems in Path of Exile.
The Traditional Gold Economy
Gold has several consequences in an action RPG setting:
- Gold Sinks: Games that use gold incur high inflation unless they have sufficient gold sinks in the form of mandatory expenses such as item repairs, paying to revive characters or continuously buying potions. These sinks are generally an unnecessary obligation and can be frustrating if a player is low on gold.
- Gold Farmers: Online RPGs often get infested by gold farmers who play the game to accumulate large quantities of gold that are then sold to other players. If gold is the main currency, it’s very simple to perform gold-accumulating tasks to supply the secondary market.
- Wealth Determinism: Earning a steady quantity of gold from monsters killed helps to re-enforce the treadmill feeling that many online RPGs suffer. People’s net worth in gold is directly proportional to the amount of time they have invested playing. This highly linear wealth gain can cause a sense of disillusionment when trying to save up a large amount of gold for a purchase – it’s apparent to the player how long it’s going to take to grind for it.
- Trade Parity: With a common gold currency, it’s easy for players to know and demand the current market value for an item. If the trade occurs at a value that differs from the current perceived market value, then one of the players feels that they got ripped off.
Bartering Currency Items
In online RPGs where gold is too easy to obtain, we observed players trading certain items as currency and ignoring the underlying gold. Some examples are the “Globs of Ectoplasm” in Guild Wars and the “Stone of Jordan” and “High Rune” economies in Diablo II.
We found that successful game pseudo-currencies have four characteristics:
- Homogeneity: Each unit of the currency has to be equivalent to other units. They should stack together, and there should never be a reason for a player to discriminate between two different units of that currency.
- Utility: The individual currency items have specific uses in addition to their trade value. If the recipient of the currency item is able to use it to improve their character, then it’s even better for them to trade for. The economic value represented by its scarcity is just an added bonus so that they are able to on-trade it if they decide not to consume it themselves.
- Scarcity: The currency should not be trivial to find. Some popular in-game barter items represent days or weeks of playing, and provide meaningful trade material for very high-end items. Other barter items are more common (cropping up every half hour or more) and allow for granularity with lower value trades.
- Handleability: It should be convenient to transport or transact with a large portion of your net worth as currency.
These three factors help make a currency acceptable. If a currency is arbitrary (players are told “this is what you should use to trade with”) but it isn’t useful, homogeneous or particularly scarce, then it’s possible they’ll pick some other currency that feels more appropriate to them. It’s important for game designers to predict the encouraged player behavior and to make sure that behavior is enjoyable.
We examined how a currency item system affects the previously mentioned consequences of a gold based economy:
- Sinks: By having every currency item inherently useful to improve a character, each currency item is its own sink. In our experience with Path of Exile, a majority of currency item trades end with the item being immediately consumed by the recipient. This also means that unnecessary gold sinks like repairing items can potentially be removed from the game.
- Gold Farmers: Although it’s still possible to farm currency items with unskilled labour, it’s substantially more complicated. Having to manage an inventory of dozens of different items with fluctuating rarities is a much larger ordeal that is difficult to deploy en-masse. Real players won't have a problem with this because they know more about the game.
- Wealth Determinism: A character’s wealth is determined by the sum of both his available currency items and also any items that he may have for trade. The unpredictable acquisition of both currency items and trade-worthy equipment helps mask the treadmill feeling that occurs when you can predict your gold gain per quest or per minute.
- Trade Parity: The relative value of currency items fluctuates constantly as new and interesting applications are found for them. It’s also subjective for each player – they all have own current item goals and each currency item may help them achieve that goal in a different way. Players can accept these barter trades because they either meet an immediate need for a currency item to use or because the items are of roughly equal value and can be later traded to someone else.
Path of Exile's Currency Items
Our implementation of this concept embraces it fully. While killing monsters in Path of Exile, you occasionally find currency items. There are currently over a dozen different types and this number will probably grow to 25 by release. It’s worth pointing out that these items are not for sale in our microtransaction store – they’re entirely in-game currency found and traded for by players.
Our currency items meet the three criteria of good game barter currencies. They are homogeneous and handleable (you can stack them). They are useful (each performs a specific action on an item or a character) and they are substantially scarcer than gold. Some of them are relatively common – you’ll probably find at least one per half hour of playing. Others are rarer, taking potentially days of gameplay to find, if you’re lucky. A few are so valuable that casual players may never find them, but only hear of them in high-end trades.
Each currency item performs a function that can help improve your character. Some examples from our current alpha version, in order of rarity, are:
- Scroll of Wisdom: Identifies a magic, rare or unique item. People actually do trade these.
- Whetstone: Increases the quality of a weapon. For example, it can upgrade a +10% damage sword to +13%. These quality values cap at 20%.
- Armour Shard: Increases the quality of an armour piece.
- Orb of Augmentation: Adds a mod to a magic item that has only one prefix or suffix. For example, it could turn Short Sword of Frost into Sharp Short Sword of Frost.
- Orb of Transmutation: Upgrades a base item into a magic item. It could turn a Recurve Bow into a Burning Recurve Bow of Anger.
- Jeweler’s Orb: Randomises the socket arrangement on an item.
- Orb of Alchemy: Upgrades a base item into a rare item.
- Chaos Sphere: Rerolls a rare item to have new random properties.
- Exalted Orb: Adds a mod to a rare item, if it has less than the maximum.
Results from Testing
So far, we’re very pleased with the results of this system. Because of the pseudorandom slot-machine-like nature of currency item drops, players get a rush from finding them. We keep hearing players excitedly showing off the valuable orbs they have found. This is more rewarding than slowly grinding up their gold value until it hits 100,000.
Players seem very keen to trade their currency items with each other. Because they all have their own metrics for how much each effect is worth, it’s common to see quite complex barters occurring with several different types of currency items.
Recently I was trying to upgrade my rare sword in Path of Exile. I had two Chaos Spheres available, which could reroll its mods randomly. While I was certain that I could improve the terrible mods that it had currently, I was apprehensive about potentially wasting my most powerful currency items. I asked around and found another tester who was happy to offer me a substantially better sword in exchange for those two Chaos Spheres. I knew that it’d take an extremely lucky roll to beat the mods on his sword, so I accepted the trade. What was in it for him? He really wanted to reroll his bow and already had a better sword than the one he traded to me.
Some players immediately use all their currency items on the spot to improve their character. These players generally have quite powerful characters and items, but are always low on actual currency items to trade. They’re often seen trading powerful upgraded items for currency, in an attempt to reroll/upgrade other items and fuel their addiction.
Other players prefer to save up all their currency items and rely on trading them for specific desired items. These risk-averse players often have several weak items on their character, but a powerful amount of disposable currency for purchasing great items when they crop up in trade. They can also perform substantial spot-rerolling if they really need something in a hurry.
Because we’re not using gold like other games, we were able to re-evaluate each of the game mechanics commonly used as a gold sink. We found that almost without exception, they are all negative mechanics that impose a burden on the player and don’t increase enjoyment. We scrapped the concept of repairing items. Our flasks can be refilled so you don’t need to buy dozens of them each time you travel to town. We don’t tax your currency when you die. Rather than charging large gold fees to perform certain actions like rerolling an item, we offer it in the form of a currency item you can find over time or trade for.
We haven’t had any players ask where the gold is. We honestly thought that people would be very uneasy with a gold-less game, but so far our testers have understood and enjoyed this system.
We are still uncertain about whether it’s worth including something like gold coins as a very low-tier currency item to help ease players into the system. If we did, they’d be itemized (and stackable) so that it’s not practical to carry too many (and would generally be spent on low-end staple items to help the player in the first few acts). We’ll hopefully be able to make a decision soon after more playtesting.
While talking about the game economy, it’s worth noting that we’re strongly opposed to any form of binding of items. Some games cite it as an effective item sink, but we believe that the inability to trade an item after use greatly hinders the economy. We want players to be able to trade for an extremely valuable item without taking a massive hit to their net worth by equipping it.
In the near future we’ll update the Path of Exile site with more information about the functionality of currency items planned at release.