Microeconomics Problem-Set Method

For intro microeconomics, start every problem by naming the market, the decision-maker, and the margin. Most mistakes come from shifting the wrong curve or confusing movement along a curve with a shift of the curve.

Supply and demand

Draw the original equilibrium first. Then ask whether the event changes buyers' willingness to pay or sellers' willingness to supply. A change in income, tastes, expectations, or substitutes shifts demand. A change in input cost, technology, taxes, or number of sellers shifts supply.

Elasticity

Elasticity is about percentage responsiveness, not slope alone. Always ask whether the answer describes quantity demanded, quantity supplied, total revenue, or tax incidence.

Welfare

Shade consumer surplus, producer surplus, government revenue, and deadweight loss. If a policy blocks mutually beneficial trades, there is likely deadweight loss. Explain the area verbally before doing arithmetic.

Exams

Write short causal chains: event, curve shift, new equilibrium, welfare effect. If you can say that chain clearly, the graph and calculation usually follow.