What you’ll learn6 learning objectivesChoose one objective for a focused lesson, or study the complete topic.2.3.1Market equilibrium• Demand and supply curves form market equilibrium• Equilibrium price and quantity coordinate buyers and sellers• Diagram: market equilibriumSyllabus objective2.3.2Changes in equilibrium• Shifts in demand or supply create new market equilibrium• Excess demand causes shortages; excess supply causes surpluses• Diagram: changes in equilibrium and the role of the price mechanismSyllabus objective2.3.3Price mechanism• The price mechanism allocates resources through signalling and incentives• Rationing is another function of the price mechanism for scarce goods and servicesSyllabus objective2.3.4Consumer and producer surplus• Consumer surplus and producer surplus measure welfare gains in a market• Social or community surplus combines consumer and producer surplus• Diagram: consumer surplus and producer surplus as social or community surplusSyllabus objective2.3.5Allocative efficiency• Allocative efficiency occurs at competitive market equilibrium when social surplus is maximized• Marginal benefit equals marginal cost at the allocatively efficient output• Diagram: social or community surplus maximized at competitive market equilibriumSyllabus objective2.3.6(HL)—Surplus calculations• Calculate consumer surplus and producer surplus from a diagramSyllabus objective