Market failure: asymmetric information

A situation where one party in a transaction has MORE or BETTER information than the other. This imbalance of power distorts the market outcome, leading to wrong quantity, wrong quality, or even market collapse.

It causes misallocation — the wrong goods or wrong quality get produced/traded. Good products are under-supplied (lemons problem), risky behaviour is over-supplied (moral hazard), and markets may produce quantities that diverge significantly from the social optimum.

A problem that occurs BEFORE a transaction when the party with less information is more likely to select an unfavourable option. E.g. high-risk individuals are more likely to buy insurance, driving up costs for everyone and causing low-risk people to drop out.

A problem that occurs AFTER a transaction when one party changes their behaviour because they are protected from the consequences. E.g. an insured driver takes more risks because the insurance company bears the cost of accidents.

Either direction. SELLER knows more: used-car markets, financial products (seller knows true quality, buyer doesn't). BUYER knows more: insurance markets (buyer knows their own risk level, insurer doesn't). Both lead to market failure.

1) Under-provision of good-quality goods (sellers withdraw). 2) Over-provision of risky behaviour (moral hazard). 3) Higher prices (insurers raise premiums). 4) Market collapse — in extreme cases the entire market disappears (no market for good used cars).

Adverse selection = hidden INFORMATION before the deal (wrong people enter). Moral hazard = hidden ACTION after the deal (people change behaviour). Both stem from asymmetric information but occur at different stages of the transaction.

In the used-car market, sellers know if their car is good or a "lemon" (bad), but buyers can't tell. Buyers only pay an average price → good-car owners withdraw → only lemons remain → the market for good cars COLLAPSES. Demonstrates how information asymmetry destroys markets.

Using the lemons example: buyers offer an average price → owners of good cars withdraw (price too low) → only bad cars remain → buyers lower their offer further → more sellers exit → eventually no trade occurs. The market unravels from the inside.

For markets to be efficient, both parties need the same relevant information. When one side knows more, the market produces the wrong quantity (too much risk, too few good products), wrong quality (lemons dominate), or collapses entirely. Allocative efficiency is not achieved.

When protected from consequences (insurance, bailouts), people take MORE risk than they would otherwise. The cost of failure is shifted to others (insurers, taxpayers). This leads to too many risky activities — an over-provision of risk-taking relative to the social optimum.

High-risk individuals (heavy smokers, reckless drivers) are most eager to buy insurance. The pool of insured becomes riskier → premiums rise → low-risk people drop out → pool gets even riskier → premiums rise further. This "death spiral" can collapse the market.

Banks that expect government bailouts ("too big to fail") may take excessive risks with depositors' money. If the bet pays off, the bank keeps the profit. If it fails, the government (taxpayers) bears the cost. This is exactly what happened in the 2008 financial crisis.

If buyers don't know quality, they can't make rational choices. If sellers don't know demand, they can't price correctly. The market mechanism relies on both sides having enough information to make optimal decisions. Without it, price signals fail to allocate resources efficiently.

In insurance: adverse selection drives up premiums for everyone. Low-risk individuals end up subsidising high-risk individuals or dropping out entirely. The market price does not reflect their true risk level, so they pay too much or go without insurance.

By forcing transparency: mandatory disclosure (ingredients, safety data, financial reports), professional licensing (doctors, lawyers must be certified), consumer protection laws (cooling-off periods, refund rights), and financial regulation (loan terms must be clear).

Actions taken by the INFORMED party to credibly reveal their quality to the uninformed party. Examples: a used-car warranty signals the seller is confident; a university degree signals ability to employers; brand reputation signals product quality.

1) No government intervention needed — lower bureaucratic cost. 2) Signalling and screening use market incentives to reveal information naturally. 3) Warranties and branding give consumers confidence, increasing market participation and trade.

Laws requiring companies to reveal information to consumers. Examples: food labelling (ingredients, allergens, nutritional values), financial reports (publicly listed companies must publish accounts), and product safety data. This reduces the information gap between buyer and seller.

1) Signalling can be expensive (university education) and may not reflect true quality. 2) Screening isn't foolproof — people can game the system. 3) Some asymmetries are impossible to eliminate (a patient can never fully judge a doctor). 4) Not all markets develop these mechanisms.

Actions taken by the UNINFORMED party to sort or distinguish between types. Examples: insurers offer different deductibles (high-risk choose low deductibles, revealing themselves), employers use probation periods, banks require collateral for loans.

Neither is universally better — it depends on the specific market. Regulation works best where stakes are high (healthcare, finance). Market solutions work best where signalling is credible (used cars, employment). The best approach often combines both.

Signalling: the INFORMED party acts (seller offers warranty, graduate shows degree). Screening: the UNINFORMED party acts (insurer offers menu of policies, employer sets probation). Both reduce information asymmetry but the initiative comes from different sides.

Consumers cannot judge a doctor's or lawyer's competence directly. Licensing requires professionals to pass exams and meet standards before practising. The licence signals competence to consumers, reducing the information gap and preventing unqualified providers from entering.

The EU's MiFID II regulation requires financial advisors to disclose all fees, commissions, and conflicts of interest to clients. This directly addresses the information gap between advisor (who knows the true costs) and consumer (who doesn't).

George Akerlof — the lemons problem (why bad products drive out good). Michael Spence — signalling theory (education as a signal of productivity). Joseph Stiglitz — screening and insurance markets. All three shared the 2001 Nobel Prize for their work on information asymmetry.

By offering a warranty, the seller bears the risk of future breakdowns. Only a seller with a genuinely good car would do this — a lemon owner would expect costly claims. So the warranty CREDIBLY reveals quality, allowing good cars to be sold at a higher price.

Define asymmetric information → explain adverse selection AND moral hazard with examples → discuss government solutions (regulation, disclosure) → discuss market solutions (signalling, screening) → evaluate which approach works better for the specific market in question.

They offer different policy options with varying deductibles. High-risk individuals choose low deductibles (more coverage, higher premium). Low-risk people choose high deductibles (cheaper premium). By self-selecting, customers reveal their own risk level to the insurer.

Regulation is costly to enforce, creates bureaucratic burden for firms, may not keep pace with new products/markets, and some information asymmetries are impossible to fully eliminate (e.g. a patient can never fully assess a doctor's competence).