Construction order: label axes and units → draw the required curves → label beside curve ends → mark equilibrium coordinates with dotted guides → add shift arrows or identify areas. For flow charts, follow the direction of the economic relationship; do not invent price or quantity axes.
Select the diagram that explains the question. Reproduce the essential labels and explain the mechanism in words. This index points to representative diagrams; paired and alternative cases remain beside them in the chapter.
| Use when explaining | Essential labels and checks | Diagram |
|---|---|---|
| Opportunity cost, unused resources and capacity growth | Both goods; frontier(s); inside/on/outside points; direction of change. | p. 11 |
| An own-price change | P and Q; D; both coordinates; movement arrow. | p. 27 |
| A non-price demand change | D1 and D2; shift arrow; P and Q axes. | p. 28 |
| PED along a straight demand curve | Elastic, unit-elastic and inelastic ranges; do not equate slope with PED. | p. 36 |
| A market shock and new equilibrium | D and S; shifted curve and arrow; P1/P2 and Q1/Q2. | p. 55 |
| Consumer surplus before and after | Relevant D and S; both equilibria; complete CS areas. | p. 61 |
| Producer surplus before and after | Relevant D and S; both equilibria; complete PS areas. | p. 62 |
| Negative production externality | MSC, MPC and MSB; market/social Q; welfare-loss triangle. | p. 72 |
| Positive consumption externality | MSB, MPB and MSC; market/social Q; welfare-loss triangle. | p. 72 |
| Specific tax and incidence | Original/taxed S; D; buyer/producer prices; tax wedge; new Q. | p. 82 |
| Subsidy and incidence | Original/subsidised S; D; buyer/producer prices; wedge; new Q. | p. 86 |
| A binding maximum price | Price below equilibrium; Qd, Qs and shortage. | p. 87 |
| A binding minimum price | Price above equilibrium; Qd, Qs and surplus. | p. 87 |