Mecanismo de cantidad: cuotas

Quotas limit production to align private decisions with social welfare. For fishing, quotas restrict the number of fish caught, preventing overfishing and ensuring long-term sustainability. By incorporating external costs into market decisions, quotas force the market quantity to match the socially optimal level where social marginal cost equals marginal benefit to consumers.

Negative externality quotas restrict production by producers to reduce harm, like emissions quotas limiting factory pollution. Positive externality quotas encourage consumption to increase benefits, such as compulsory vaccination programs ensuring adequate immunization rates. Both align private decisions with social welfare, but in opposite directions based on whether the externality causes harm or benefit.

The socially optimal quota is found by adding external marginal cost to private marginal cost to form the social marginal cost curve. The intersection of this curve with market demand reveals the socially optimal quantity. This quantity becomes the quota limit, ensuring the market supply curve becomes vertical at this level, achieving efficiency.

Quotas encouraging positive externalities include mandatory school attendance until a certain age, promoting education and civic engagement; compulsory vaccinations, controlling disease spread and creating herd immunity; and mandatory auto liability insurance purchases, ensuring third-party risk coverage. These quotas increase consumption to reach socially optimal levels.

Without quotas, fishermen catch fish where their private marginal cost intersects market demand, ignoring external costs to society like ecosystem damage and resource depletion. This results in overproduction because private costs are lower than social costs. Quotas correct this by restricting quantity to where social marginal cost equals demand, protecting biodiversity and sustainability.

Quotas set a strict production or consumption limit, making the market supply curve vertical at that quantity. This contrasts with price-based interventions like taxes or subsidies, which adjust incentives but allow quantity to adjust. Quotas guarantee a specific quantity is achieved, providing certainty about the level of production or consumption regardless of market conditions.

Emissions quotas limit pollution from factories by capping production levels or requiring pollution reduction. Noise restrictions reduce disturbances in residential areas. Fishing quotas protect fish populations and ecosystems from overexploitation. These quotas force producers to internalize external costs, aligning private production decisions with environmental protection and societal welfare.