Game Economy

• An economy consists of a set of basic elements
  • Resources - any concept that can be measured numerically. Anything that the players can produce, gather, collect or destroy.
    • Tangible resources - have physical properties in the game world. They exist in a particular location and have to be moved somewhere else.
    • Intangible resources - have no physical properties in the game world. They do not occupy a space or exist in a particular location. These are just numbers.
    • Abstract resources - do not really exist in game but are computed from the current state of the game (i.e., a strategic advantage). They are mainly used for internal computation.
    • Concrete resources - really do exist in the game which the players can experience or interact with.
  • Entities - where specific quantities of a resource are stored (i.e., a variable).
    • Simple entities - store only one value.
    • Compound entities - groups of related simple entities called attributes.
  • Economic functions - functions that affect resources that move them around.
    • Sources - mechanics that, under certain conditions, create new resources out of nothing and store them in an entity
    • Drains - mechanics that, under certain conditions, take resources out of the game, reducing the amount stored in an entity.
    • Converters - mechanics that turn resources from one kind to another (destroying one and creating another)
    • Traders - mechanics that move a resource from one entity to another, and another resource back in the opposite direction according to an exchange rules.
    • Sources and drains share similar properties:
      • They may be triggered by events in the game, or may operate continuously based on a production or consumption rate.
      • They may also be toggled on or off

Feedback §

• The economy of a game (in particular the dynamics of a particular resources) can be plotted over time to visualize it better and to discover underlying patterns .

Negative Feedback	Positive Feedback
Creates stability	Creates an arms race
Characterized by convergence to an equilibrium	Characterized by exponential growth or decay
Can create a dynamic equilibrium when fed the difference of resources (as in one resource ends up compensating for the lack of another). Allows for balancing as well	Can be used to create deadlocks and dependencies between resources (i.e., one resource depends on another resource)
Allows for rubberbanding where players are neither too far ahead or too far behind. Creating excitement	Can be used to make players win or lose quickly.
More or less creates an even playing field.	Makes it so that one player’s advantage snowballs
Can prolong the game	Can end the game quickly or destabilize it.
Magnifies late game successes	Magnifies early game successes
Leads to adaptive or goal seeking behavior

• It is important to consider how short term investments on a particular resources can impact gameplay in the long term.

• Feedback loops can be characterized in more detail as follows

  • Type - Positive / Negative
  • Effect - Constructive / Destructive. Creates an effect that will help a player win / lose
    • If the feedback is tied to a winning condition it is probably constructive. Otherwise, if it is tied to a losing condition, it is probably destructive.
  • Investment - High / Low - many / few resources must be invested to activate the feedback
    • Investment is proportional to the number of resources required to activate the feedback loop (high = more)
  • Return - High / Low / Insufficient - the net gain is high / low / negative
    • Return is proportional to the number of resources gained or produced from the feedback loop and in relation to the investment.
  • Speed - Immediate / Fast / Slow - the feedback is in effect immediately / after a little time / after a lot of time
    • The speed of a feedback loop is inversely proportional to the number of actions and elements involved to activate it (more = slower)
  • Range - Short / Long - the feedback operates directly / indirectly over few / many time steps
    • Feedback loops that consist of many elements have a high range.
  • Durability - None / Limited / Extended / Permanent - the feedback only works once / over a short period of time / over a long period of time / permanently.
    • The durability of a feedback loop is usually permanent unless it depends on a limited resource that cannot be obtained (i.e., it depreciates). In such a case, the consumption rate of the resource and the amount lost per time unit determine how durable the loop is/
  • Strength - an informal indication of the feedback to the impact of the game.
  • Determinability - the strength of a feedback loop may be affected by different factors.
    • Deterministic - given a certain state, the mechanism will always act the same
    • Random - the mechanism depends on random factors. This can affect speed or return (more randomness may mean infrequent return)
    • Multiplayer-Dynamic - the type, strength or effect of the mechanism are affected by direct interaction with other players.
    • Strategy - the type, strength or game effect of the mechanism are affected by the tactical or strategic interactions between players
    • Player Skill - the type, strength or game effect of the mechanism are affected by the player’s manual skill in executing the actions.

Applications §

• Economies can be integrated in the game in a variety of ways, often interacting with other mechanics

  • Use it to complement physics (skillfully performing physical actions gives you a resource). The physics system may also invoke risk and reward for the player.
  • Use it to influence progression. Acquiring or removing certain resources may facilitate further progress into the game level or introduce new opportunities for exploration.
    • Just make sure to not cause a deadlock in this case by making the resources required for progression immediately available.
  • Use it to add strategic gameplay. Economies allow for reward planning and long-term investments. Complex economies can sustain complex strategic behaviors.
  • Use it to create a large possibility space. More complex economies lend themselves to larger posssibility spaces and more replay value. Keep in mind the following
    • If a particular combination of items and skills is more efficient than others, players will choose only that option and the economy will be thrown off balance.
    • You have to be sure that the possibility space is large enough that player does not end up exploring it entirely in one play session.
      • Consider having choices that exclude each other to make them feel like they have real consequences.
    • Design the levels in such a way that players can use different strategies to complete them.

• Some tips for making games where the player builds an economy and keep the complexity under control

  • Don’t introduce all the player’s building blocks at once. Gently introduce players to the different game elements. Lock advanced elements behind progression mechanics.
  • Be aware of the meta-economic structure. Keep in mind that certain approaches are better than others.
    • One way to balance this is to make structures that are effective in the early game be less effective in the late game. Use slow-working, destructive positive feedback.
  • Use maps to produce variety and constrain the possibility space.

Case Studies §

• Power Ups and Collectibles - they create an internal economy centered around risk and reward.
  • More valued Collectibles can be tied to high risk.
  • Some powerups may be needed. Others may not be needed but are still helpful but are risky to obtain.
  • Powerups lend themselves well to temporary positive feedback loops.
  • For the return, the risk is balanced by the player skill.
• Racing Games - they can be framed as the players aiming to produce distance.
  • The production rate is influenced by chance, skill, strategy, and quality of the player’s vehicle.
  • Rubber banding allows a “close race” so that players that are behind can catch up.
• RPG elements - the economy consists of skills and other attributes of player characters.
  • It must contain a positive feedback loop - player characters perform task successfully to increase abilities to increase their chance to perform more tasks successfully.
  • A negative feedback loop counters the above positive feedback loop. The experience required to level up increases or the number of actions required to gain experience increases.
  • This strategy favors specialization, especially when skills are harder to obtain.
• FPS economy - there is an economy between fighting aggressively and losing health.
  • Enemies may provide a source for ammo and health. At the same time, shooting constitutes a drain for ammo.
  • Health and ammo drops may be provided, however their effectiveness depends on player skill.
• RTS economy - harvesting resources in the game constitutes an economy
  • Most will require that players allocate their harvesters to harvest different resources.
  • The resources are converted to a building which can be used to create more units and buildings
  • The production of a unit costs resources. However, they can be used offensively or defensively to counter other units.
  • Technology trees introduce dependency chains but can also serve as an element to a feedback loop (albeit one that requires high investment).

Links §

• Adams and Dormans Ch. 4, 6-7

• Internal Economy Design Patterns

• System Dynamics - more on feedback loops.