本章主要讨论了充分的 市场效率 重要性；以租房市场为例，演绎了 政府干预 的方式以及结果；并介绍了 市场失灵 的概念以及相应的调控手段。
Under some conditions, the free market leads to an efficient equilibrium. Why does the government ever intervene?
- Conditions do not hold and the market equilibrium is inefficient → market failure
- Government dislike the equilibrium despite it being efficient → distribution
Deadweight Loss
In the presence of a market failure, policy can potentially restore efficiency. Otherwise, policy involves an equity-efficiency trade-off: market surplus is sacrificed to achieve distributional objectives.
We refer to the decrease in market surplus created by a policy as the deadweight loss (无谓损失).
无谓损失（Deadweight Loss）是指由于市场未处于最优运行状态而导致的社会福利损失。它体现为消费者和生产者都无法获得的经济价值，是社会经济福利的净损失。
Why do business leaders need to think about government intervention?
Government intervention is ubiquitous and shapes the business environment in important ways. Understanding what motivates policy and how it affect markets allows firms to:
- influence policy outcomes
- account for the likely impact of new policy in their decisions (about market entry, investment etc)
We start from the competitive market framework and ask:
- What could motivate government intervention?
- How is the market affected? Is there a deadweight loss and, if yes, how large?
- How are firms affected? What determines firms’ exposure?
Applications (Rent Control)
Take rent control as an example, as:
- People care deeply about how and where they live
- Rents constitute large share of household budgets and rentals are big business
- Rent controls shape cities
And understand the impact of the different policies:
- Price Controls: direct government regulation of prices → rent controls
- Subsidies: promoting specific goods through subsidies → housing benefits
- TaxesTaxes: discouraging specific actions through taxation → carbon taxes
Other examples: price-gouging regulation, medicine price caps, minimum wages.
Conclusion
- Government interventions can be motivated by market failures or distributional concerns.
- Range of policy instruments: price controls, taxes, subsidies.
- Firm exposure to government interventions depends on the relative steepness of demand and supply curves.