Chapter 7 — Key Takeaways
Price ceilings (price caps)
A price ceiling is a legal maximum on a price. It binds when set below the equilibrium price.
Effects of a binding price ceiling: 1. Quantity supplied falls (movement along the supply curve) 2. Quantity demanded rises 3. The gap is a shortage 4. Some renters benefit (those who get the controlled-price units) 5. Some prospective renters are hurt (those who can't find available units) 6. In the long run, supply gets even worse (landlords exit, no new construction) 7. Quality often declines 8. Search costs and waiting lists rise
Rent control specifically: the IGM Forum 2012 poll found ~95% of economists agreed that rent control reduces the supply and quality of broadly affordable rental housing. The empirical record (Diamond-McQuade-Qian 2019 on San Francisco; Berlin 2020) supports the standard critique.
Why voters support it anyway: present rent bills are concrete, future shortages are abstract; bargaining power is asymmetric; stability has real value; distributional concerns matter; and the standard model abstracts from features voters notice.
Better alternatives: zoning reform to increase supply, housing vouchers to subsidize tenants directly, or rent stabilization (not strict control) that protects current tenants while allowing market adjustment.
Price floors
A price floor is a legal minimum on a price. It binds when set above the equilibrium price.
The minimum wage is the most consequential price floor. The simple supply-and-demand model predicts it causes unemployment, with the size depending on the elasticity of labor demand.
The empirical evolution of the consensus: - Pre-1994: economists believed labor demand was fairly elastic; minimum wages were thought to cause meaningful job losses - Card-Krueger (1994): no significant effect on fast-food employment in NJ - Replication wars (1995–2010): mixed findings, methodological disputes - Dube et al. (2010), Seattle MWS, CBO (2019, 2021): generally small effects for moderate increases - Current consensus: moderate minimum wage increases (to $12 or $15 in markets with median wages well above) cause small employment losses outweighed by wage gains; very large increases (above $20) are more uncertain
Why is the elasticity smaller than the simple model predicts? Monopsony power, productivity adjustments, price pass-through, and search frictions in labor markets.
Tax incidence
The tax incidence rule: the more inelastic side of the market bears more of the tax burden.
- Cigarettes (inelastic demand) → buyers pay most of the tax
- Luxury yachts (elastic demand, inelastic supply) → producers pay most of the tax (the 1991 U.S. luxury tax episode)
Statutory incidence (who legally writes the check) and economic incidence (who actually pays) are different things.
Subsidies
A subsidy is a tax in reverse. The more inelastic side of the market captures more of the subsidy benefit. The Bennett hypothesis on student loan subsidies captured by college tuition is a famous example (we'll see it again in Chapter 36).
Deadweight loss
The deadweight loss of a tax or price control is the area between the demand and supply curves over the range of quantity that the intervention has eliminated. It represents trades that would have happened without the intervention but don't with it.
Important caveat: deadweight loss is a measure of inefficiency, not of how bad a policy is. A policy with substantial deadweight loss can still be a good idea if its benefits exceed the loss; a policy with no deadweight loss can still be a bad idea if its distribution is unjust.
What the chapter does NOT settle
The right policy in any specific case depends on: - Specific policy design - Specific market context (competitive? monopsonistic? elastic? inelastic?) - Specific time horizon (short-run vs. long-run effects) - Specific values (efficiency, equity, stability, dignity, freedom)
The chapter teaches you how to ask the question carefully, not what the answer should be.
Themes this chapter touched
- Markets power+imperfect — interventions can fix some failures and create others
- Tradeoffs — efficiency vs. equity is the central tension
- Disagreement — rent control has strong consensus; minimum wage has nuanced consensus
- Behavioral lens — why voters support what economists oppose (present-bias, salience, asymmetric bargaining power, distributional fairness)
- Affects daily life — these are policies you encounter directly
One sentence summary
Government interventions in markets work the way the supply-and-demand model says they do — they create shortages, surpluses, deadweight losses, and incidence patterns determined by elasticity — and the right policy choice depends on which trade-offs you are willing to accept and which values you weight most heavily.
Where this leads
- Chapter 8 — Consumer and producer surplus, the formal way to measure who gains how much
- Chapter 9 — Tariffs as a special case of taxes on a particular kind of market
- Chapter 21 — The full treatment of labor markets and the minimum wage
- Chapter 36 — Housing affordability and the Bennett hypothesis on college tuition