Model resources as an internal economy — mind the sources, sinks, and flows
GDC-L1-SYS-000801
Statement
Treat every resource in the game — currency, health, ammo, time, XP, materials — as part of an internal economy of sources (where resources enter), sinks (where they leave), and converters (where one becomes another). The rates of flow through this economy govern pacing, difficulty, and progression; many problems that look like content problems are actually flow problems.
02
Rationale
An internal economy is the connective tissue that turns isolated mechanics into a system, and its structure — the balance of sources against sinks — is what generates challenge and paces progression [S-adams-dormans-mechanics]. When a game feels too easy, too grindy, too rich, or too starved, the cause is usually an imbalance in flow: a source outpacing its sinks (runaway accumulation, trivialized challenge) or sinks outpacing sources (starvation, grind). Seeing resources as an economy makes these diagnosable and tunable at the level of rates, rather than as a pile of unrelated numbers.
03
Applies when
Any game with accumulating or spent resources — which is almost all of them. Essential for RPGs, strategy, survival, simulation, and any game with progression or crafting.
04
Does not apply / Exceptions
Games with minimal or no resource accumulation (pure skill/action games, many puzzle games) have thin economies where this lens adds little. Even there, "attention" and "time" can be modeled as resources, but the framework earns its keep only when flows are substantial.
05
Implementation
Enumerate each resource's sources, sinks, and converters, and reason about rates, not just totals. Model or diagram the flows (economy-simulation tools exist for this) to spot runaway accumulation or starvation before players do. Tune pacing by adjusting flow rates rather than bolting on content. Watch for feedback loops inside the economy (SYS-0004), where a resource feeds a source of itself and snowballs.
06
Disagreement
No serious disagreement on the framework's usefulness where economies are substantial; debate lives one level down (how much scarcity, how fast progression) and belongs to the ECON and BAL domains.
07
Notes
Partners with SYS-0004 (feedback loops are the dynamics of the economy) and bridges to the future ECON and BAL domains, which will treat currencies, scarcity, and tuning in depth. Confidence 4.
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Connected principles
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