Incentives and the Cost-Benefit Principle

Incentives matter

Incentives are rewards and punishments that motivate behavior; they shape decisions and are everywhere.
Core idea: incentives help predict human behavior, sometimes more than sentiment or benevolence.

1787: Britain shipped convicts to Australia under harsh conditions; regulations failed to improve survival.
Solution: pay captains only for prisoners who arrive alive; survival jumped to 99\%.
Lesson: incentives can fundamentally change outcomes beyond intentions.

Tipping bans: service quality can drop because waitstaff respond to incentives.
Public companies: after going public, liquidity of stock changes incentives for behavior (e.g., divorce settlements).
Income effects and benefits cliffs: higher incomes can reduce or eliminate benefits, creating implicit taxes for lower-income individuals.
Property rights: incentives are what make value internalizable; rights align creators’ incentives with outcomes.
Negative incentives example: a man buying Lennon’s tooth and offering DNA tests can create costly or coercive incentives.

Framing effect: how a choice is presented can influence decisions (e.g., on sale items).
To avoid framing effects, first think about how much you’re willing to pay (WTP) before looking at prices.
Example: coffee WTP and price:
- WTP{Naz}=\$1.00,\; WTP{Betsy}=\$4.00,\; price=\$3.50.
- Both would buy given their WTP exceeds price; benefits are measured in dollars as the joy or value of the coffee, not just the price tag.
Money is a measuring stick, not a statement about money obsession; it helps compare nonfinancial benefits with costs.

Core set (applied across contexts):
- Cost-benefit principle
- Opportunity cost principle
- Marginal principle
- Independence principle
The power comes from applying these principles, not just knowing them.

For every decision, benefits should exceed costs to justify the choice.
Put everything on a common scale (often dollars) to compare nonfinancial and financial aspects.
General rule: choose options where Benefits \geq Costs; more formally, net benefit NB = Benefits - Costs \ge 0.

Benefits: enjoyment of coffee; Costs: price of coffee.
Willingness to pay reflects the monetary value of the nonfinancial benefit.
Example values (illustrative):
- WTP{Betsy}=\$4.00,\; WTP{Naz}=\$1.00,\; p=\$3.50.
Takeaway: compare price to WTP; if price is within what you’re willing to pay, purchase; otherwise not.
Important nuance: benefits are not only financial; include social or relational benefits (e.g., meeting a friend).

Framing effect (ignore headlines; focus on your own willingness to pay).
Don’t let sticker price, sales pitches, or menu framing distort your assessment.
Before choosing, ask: what are all the benefits and all the costs (both financial and nonfinancial)?
When applying the principle, avoid exaggerating benefits or ignoring costs.

Car costs discussed:
- Gas and parking: about \$500/\text{month}
- Insurance and maintenance: about \$200/\text{month}
- Total car costs: \$700/\text{month}
Alternative (Uber) costs: about \$30/\text{day} \times 20\text{ days} = \$600/\text{month}
Benefit of car: convenience and ability to travel when needed
Decision: if Uber costs are lower, not buying the car is rational; emotional attachment can mask the math

Any decision has benefits and costs; choose where benefits are at least as large as costs.
Include all benefits and all costs, not just financial ones.
Use a systematic, non-selfish framework to compare options.
Practical habit: pause and ask why you’re making a choice; you’ll often find it’s an application of the cost-benefit principle.

Cost-benefit principle: compare benefits and costs; choose where Benefits ≥ Costs.
Opportunity cost principle: consider the next-best alternative you forego when making a choice.
Marginal principle: decisions about quantities (how much to do) depend on the additional (marginal) benefits and costs.
Independence principle: decisions are interconnected; one choice affects others (e.g., consuming more coffee affects money for tea, milk, etc.).

Thinking like an economist is about applying these principles to real-life decisions to improve outcomes and understand others' behavior.