How to design an economy for your game? The answer to this question might require a series of lectures or articles. The fundamental difference in the approach is based, first of all, on monetization model: F2P or B2P. The second thing that defines the approach to developing an economy system is game genre. This article reviews the case of designing the game economy for a B2P (premium) game, which doesn’t involve earning on microtransactions.
Konstantin Sakhnov
game designer
Definitions
Let’s start with terminology. It will help us to understand the difference in approaches to developing game economies for games of different genres.
By resource balance, game economies can be categorized as follows:
Surplus – the resource is provided in the amount more than needed
Balance – the resource is provided only in the amount that the player can spend
Deficiency – the resource is provided in the amount consistently less than needed
I guess there is no need to explain that almost any F2P project employs an economy model based on deficiency of a certain resource. But this is a subject for a separate article. In Premium games on PC and consoles, such separation can also be observed. Resident Evil and Dead Space franchises are my favorite examples. Resource deficiency not only provides a balance shift, but also turns the whole gameplay experience and almost the whole genre into horror. At the same time, a surplus of ammo and first aid kits would make it rather an engrossing action.
From resource exchange perspective, game economies can be categorized as follows:
Closed-type – there is no free exchange of resources between players
Open-type – it is possible to trade and exchange a certain resource
Where to start
We should start with the core gameplay loop. Economy is a mathematical model with formulae and resource flows, and in order for it to be designed, first, we need to know all game mechanics. Designing core gameplay loops is a great task by itself. But economic loop is a part of it. Let’s take a look at the example.
What we can see on the UML diagram is the following:
● Grey – game mechanics and entities
● Purple – scenes other than the main scene (planet surface)
● Green – resources
● Beige – objects on the surface
4X strategy is quite a complex genre. The economy scheme does not include many mechanics that are involved in the economy loop, but do not affect it in a crucial manner: quests, random events, exploration of locations, anomalies, etc. If we try to show them all, the scheme will be too cluttered. This is why we focus only on the essential elements of economy.
Resources are the basis of economy
From Picture 1, we see that there are certain basic resources (energy, stone, metal) produced by sources and common buildings. They are spent on vengeance and enhancement of these buildings, sources and infrastructure (consisting of various protective and other buildings).
We can also see that the game has another type of resources called ‘advanced resources’. What are they used for? You could answer that it seems from the scheme that they are used for enhancement of buildings and planet terraforming. This is perfectly true, but this is actually a consequence. Their basic task is to create an interesting gameplay. We could simply create more basic resources and allocate some a part of them for one type of buildings, and another part for other buildings. But advanced resources are the analogue of craft mechanics. Remember Against the Storm, a highly successful indie-strategy.
Processing of certain resources into other resources makes an important part of the gameplay. It provides more fun and challenge and allows the developer to control the production of rare resources through deficiency of one of their components. Let’s say that production of copper ingots requires fuel (e.g. wood) and copper ore. We usually have a lot of wood, but copper ore is hard to find on certain maps. We have chosen the same approach.
While designing premium strategy game economies, developers usually make provision for several types of resources having different functions:
Basic – easy to collect, usually in surplus
Advanced – produced from basic resources or by harder mining
Limited – they limit the mechanics depending on the economy (e.g. combat system)
Special – designed for a particular narrow task
Thus, through the example of Sid Meier’s Civilization, we can say that points of culture, faith, science, food, gold and production are basic resources. Usually, there is enough of them available, and their generation is usually continuously growing. The advanced resources are luxury resources which increase happiness of citizens. The limited resources here are strategic resources required for creating an army. Special resources are loyalty scores of cities, number of corporations available (there are no corporations in base version of Civilization VI), etc.
The same thing can be done with most 4X strategies, for example, Endless Space II. Here, you will find the full range of resource types as well.
In our case, limited resources are represented with those required to create and maintain an army. In contrast to most of strategies, our troops consume a rare resource instead of gold. If this resource is depleted, the military unit would turn off and would not be able to move or fight.
So, here is the general principle of dealing with resources in premium strategies:
● We specify basic resources, which are supposed to be given in surplus or in balance
● We make a list of game mechanics consuming and producing the basic resources
● We make a list of game mechanics, which depend on the economy, but should not skyrocket when the economy grows
● We tie them to limited resources, not only to basic ones
● If the strategy is designed with long slow sessions and tactics in mind, it would be convenient to introduce second-level advanced resources
● All unclear situations can be covered by special resources, but we should try not to go over the top with that: remembering that stone, metal, energies and other resources work similarly would be easy for a player, but understanding mechanics of every special resource would be difficult – this adds complexity to logic, interface and training
One more important aspect are logical types of resources. They can be:
Currency – it can be obtained or spent, usually it is more than zero, can be fractional
Example: gold
Resource – it can be obtained or spent, has a whole-number value, which may not be negative
Example: lumber
Rating scale – it has a minimum and maximum or just one of these limits, usually has units of measurement (degrees, percentage, shares, g, etc.)
Example: oxygen reserve
Usually, the above-mentioned types are enough for me, but in some cases more unique types of resources may appear.
Mathematical model
It is hard to imagine an economy without mathematics. But the approach here is clear. For each type of resources, we develop its own consumption and production formula. For example, basic and advanced resources are produced by sources in the amount of 1 unit per source. However, in fact, such formulae are much more complex. Let’s see an example from the same game.
Strangely enough, mathematics in economic systems is usually not very complex. It is much more difficult to formulate a logic behind it. Let’s check out an example.
Our game has a population living on a planet. The planet is divided into zones. Each zone contains the average of 6 population units. We need humans, elves, orcs, demons and undead to achieve a simple goal: we need them to pray to us producing spiritual essence, and to die giving away their souls. Souls charge the void generator, and it produces more nano-swarm, a resource used for building armies and drawing spells. Spiritual essence is needed for crafting in order to enhance basic resources with it thus turning them into advanced ones.
So, we have 3 basic resources, which means that each zone should contain at least 3 buildings each consuming 1 unit of every basic resource and 1 spiritual essence to produce 1 unit of advanced resource. Production scale in units was selected for player’s convenience. Also, it is possible to enhance buildings in our game, and after enhancement they produce and consume more resources. Which means that each zone with 6 citizens consumes 3 + 3 = 6 units of spiritual essence. It is easy to count: 1 citizen should produce 1 unit of spiritual essence per turn (in average). Continuously fighting orcs have less time to pray, so they would give less essence and more souls dying in battles, while more devotional elves would praise you and die less frequently. But in average, the gain of souls and essence is 1 per turn for each unit of population.
Our next task is to understand the generator charging scale. What numbers should we use? From -100 to 100? It makes sense to take 0 as a start. Now, let’s find the maximum. Let us assume that we want the generator to be fully charged by the middle of a game session. In our case, we planned a session to be around 200 turns long, which means that the maximum should be achieved around the 100th turn. How many souls would the population create by then?
If there is 1 unit of population in a zone in the beginning, and the average growth is 1 unit per ten turns (orcs grow faster, elves – a little slower), then the population would provide 1 soul per turn within the first 10 turns. Within the next 10 turns, after another citizen is born, we get 2 souls per turn, and so on, until the 100th turn. Now, we have an arithmetic progression:
We can see that the maximum generator charge should be around 550. For player’s convenience, let’s take 500.
Let me remind you that we need to charge the generator with souls to make it produce more nano-swarm per turn. Now, we need to calculate, how the charge scale converts to nano-swarm production. To do so, we need to select the following:
● Set the value scope: what production rates shall we have at the minimum and maximum values of the charge scale?
● What would be the type of production-charge dependence?
For convenience, I took the following values:
● At 4 charge points, 2 nano-swarm is produced
● At 128 charge points, 7 nano-swarm is produced
I guess that those who know the powers of two already have an understanding that I took logarithm to the base 2 as a curve that defines the dependence. I looked at the results at full generator charge (500) and realized that I want to see slightly larger numbers. The logarithm is suitable in this case, since it solves several tasks at once:
● It is easy to increase swarm production in the beginning
● The more we want it to grow, the more challenge it takes
● When we reach the maximum, we can upgrade talents for resources, since the player has probably collected an excessive amount of resources
By playing with numbers for a while, I found the solution: logarithm base became 1.75 instead of 2.
In the section above, I have described only one small part of work on the economic model for a particular game. Of course, many readers would expect this article to provide an universal logic of how to create an economy for any premium game. Unfortunately, it is impossible to develop an universal algorithm: there is quite a diversity of games, as well as their goals and developer approaches. And that’s wonderful, if you ask me.
Playtests
I am sure you’ve noticed that I admitted a few assumptions above. For example, the assumption that one would like to charge the generator by the 100th turn or so. Such assumptions are called input assumptions. Without them, it would be almost impossible to design a game system. Why does a LVL 1 miner produce 1 resource unit per turn? Well, that’s because this number seemed to the game designer convenient for calculations and comprehensible for the player. This way, we established the scale for the whole economy, whether we realize that or not.
Similarly, we select progression factors: population growth of 1 in 10 turns, average building cost of 5 resource units, base 1.75 in nano-swarm production logarithm, etc. All of these are assumptions too. They are called economy balance factors.
And no matter how long we work on the economy, it would be hard to have all bases covered. But the main thing is that we don’t need to. We must fix all the input and all balance factors in order to know what to change while bringing the economy into balance. All other things, such as logic and relations between formulae and resources, are the economic model itself.
There is only one way to make sure that the theoretically-designed economy actually works: to implement it in the game. And then, to play a lot to rework as much game situations that the player might encounter as possible.
The general principle of balance here is simple. If the model works, then we tune all the dissatisfying elements by modifying factor values. Then, we play again and decide what to tune next. You should not change the formulae or break the logic, and most of all you shouldn’t add new entities adding complexity to the economic model, until you ensure that the problem is not in ill-chosen factor values. If the current model doesn’t work, the why should a more complex modified model work rather than becoming a mere kludge? I should admit that game designers, including myself, due to deadlines and budget limitations, often make kludges in places that should instead have been balance-tested more. This is excusable for small studios hog-tied by investors. But when we see such problems in AAA games with huge budgets and deadlines, a question arises: perhaps it could have been avoided?
Tools
Finally, I would like to note that most game mechanics sometimes can be tested, at least in part, by prototypes or special platforms for game designers.
Most of you probably know Miro, Figma and other services, where it is easy to draw gameplay diagrams. But less is known about economy design services.
I cannot but recommend https://machinations.io/ – a web-platform, where you can you're your own economic model. It helped me prototype not all, but many things, in particular, it is very convenient to perform random testing there.
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