Economics: Externality Simulators

Explore three powerful interactive economics tools designed to transform learning into engaging, visual experiences: the Externality Diagram Explorer, Free Rider Simulator, and Tragedy of the Commons Game. Perfect for classrooms or online platforms, these HTML games bring abstract concepts like market failure, public goods, and sustainability to life with real-world scenarios and intuitive interactivity.

All HTML simulators are accompanied by a supporting PDF document, designed to help teachers integrate the resource effectively into the classroom with ideas for use, key discussion questions, and reflection prompts.

Tragedy of the Commons: Strategic Fishing Game:

Purpose: A round-based strategy game that models the Tragedy of the Commons in a competitive resource extraction scenario.

Key Features:

Player vs AI Competition: Choose fishing strategies (Conservative to Maximum) each round while AI competitors adapt based on personality and ecosystem state.

Dynamic Fish Population: Real-time updates on fish levels, ecosystem health, and sustainability warnings.

Economic Metrics: Tracks profit, reputation, and market price changes depending on fish scarcity.

Scenario Modes: Includes Cooperative, Regulated, Competitive, and Crisis markets to model different institutional settings.

Endgame Analysis: Evaluates the player’s strategy in terms of environmental impact and financial gain.

This simulation gamifies the challenge of managing common resources sustainably. It teaches trade-offs between short-term profit and long-term viability in a vivid, interactive format.

Street Light Public Goods Simulator:

Purpose: A narrative-driven game that simulates the free rider problem in public goods provision.

Key Features:

Interactive Story: The player is faced with choices about funding a streetlight, reflecting dilemmas around shared benefits and private costs.

Dynamic Reactions: Neighbours' responses and animations (e.g., dark houses, glowing streetlight, thought bubbles) respond to the player’s decisions.

Ongoing Costs: Includes decisions about maintenance and electricity bills to show the long-term burden of providing public goods.

Endgame Lesson: Concludes with a summary of real-world solutions (government provision, associations, regulation).

Educational Value:
This simulation immerses students in the public goods dilemma and illustrates the free rider problem using behavioral and economic principles. Ideal for classroom demonstrations.

Interactive Externality Diagram:

Purpose: An interactive economics diagram tool to explore different types of externalities.

Key Features:

Dynamic Diagram Controls: Users can manipulate sliders to adjust the slopes of Marginal Private Cost (MPC), Marginal Private Benefit (MPB), and the magnitude of the externality.

Real-World Scenarios: Clickable example cards (e.g., Pollution, Smoking, R&D) pre-load predefined values and contextual explanations.

Four Externality Types Covered:

Negative Production

Negative Consumption

Positive Production

Positive Consumption

SVG-Based Graph: Automatically updates and displays curves for MPC, MPB, MSC, and MSB with labeled equilibrium points.

Legend and Info Panel: Explains each curve and the economic implications (e.g., overproduction, underconsumption)

Maplewood Green Fund Public Good Simulator

One of the main benefits of this simulator is that it transforms an abstract economic dilemma—the free-rider problem in public goods provision—into a concrete and engaging experience. Rather than reading about theories, learners actively make decisions, adjust contributions, and see how their choices affect both individual and collective outcomes. This interactivity deepens engagement and sustains attention far more than traditional text-based explanations.

The game also highlights the tension between private incentives and social benefits. For example, every dollar contributed generates more social value than private return, meaning players must grapple with the classic collective action problem. By seeing their outcomes evolve round by round, students can connect theory to lived decision-making and directly observe consequences such as free-riding or cooperative success.

In addition, the environmental framing of the game adds relevance. Linking contributions to trees planted, solar panels installed, and bike lanes created ties economics to real-world sustainability issues. This helps students appreciate not only the mechanics of public goods but also the broader ethical and social stakes involved.

Finally, the built-in reflection features—such as year-end reports, dynamic insights about player behaviour, and discussion questions—encourage critical thinking. Learners are guided beyond “winning” the game to reflect on social norms, policy interventions like government matching, and parallels with climate change or taxation.

Through this simulator, learners develop a range of outcomes that align with both economic understanding and transferable skills. They gain conceptual clarity on the free-rider problem, distinguishing between social returns and private returns. They also learn how collective action problems manifest when incentives are misaligned, and how policies such as matching grants can influence behaviour without completely solving the dilemma.