INSECT is a mnemonic for the six determinants that shift the entire demand curve in AP Macro Topic 1.4: Income, Number of consumers, Substitutes (price of), Expectations, Complementary goods (price of), and Tastes/preferences. Price is NOT on the list; price changes cause movement along the curve.
INSECT is a memory trick for the determinants of demand, the six non-price factors that shift the whole demand curve left or right. Each letter is one shifter: Income, Number of consumers, price of Substitutes, Expectations of future prices or income, price of Complementary goods, and Tastes/preferences. When any of these changes, the demand curve itself moves, meaning consumers buy a different quantity at every price.
Notice what's missing from the list. Price. That's the whole point of the acronym. A change in a good's own price moves you along the existing demand curve (a change in quantity demanded). A change in any INSECT factor shifts the curve (a change in demand). This matches EK MKT-2.B.1, which says factors like changes in consumer income cause the market demand curve to shift. If you can run through INSECT and the change isn't on the list, it's almost certainly a price change, so don't shift the curve.
INSECT lives in Topic 1.4 (Demand) in Unit 1: Basic Economic Concepts, directly supporting learning objective 1.4.C, which asks you to explain the determinants of demand using graphs. It also protects you from violating 1.4.A and 1.4.B, the law of demand, because the most common Unit 1 error is shifting the demand curve when only price changed. Unit 1 is the foundation for everything else in AP Macro. Every market graph you draw for the rest of the course (loanable funds, foreign exchange, aggregate demand) uses this same shift-versus-movement logic, so getting INSECT down early pays off all year.
Keep studying AP Macroeconomics Unit 1
Demand Curve (Unit 1)
INSECT tells you when the demand curve actually moves. An increase in any positive shifter (more income for a normal good, more buyers, better tastes) slides the entire curve right; the reverse slides it left. Price never shifts it.
Substitutes and Complementary Goods (Unit 1)
The S and C in INSECT are about the prices of other goods. If the price of a substitute (Pepsi) rises, demand for your good (Coke) increases. If the price of a complement (hot dogs) rises, demand for the paired good (hot dog buns) falls.
Expectations of Future Price (Unit 1)
The E covers what consumers think will happen later. If buyers expect prices to rise next month, demand increases today, even though nothing about the current price changed. This is the shifter students most often forget.
Aggregate Demand Shifters (Unit 3)
The same logic scales up. Aggregate demand has its own list of non-price shifters (like consumer confidence and wealth), while changes in the price level move you along the AD curve. If you mastered INSECT in Unit 1, the AD/AS model will feel familiar.
The acronym itself never appears on the exam; it's a study tool. What gets tested is the skill behind it. MCQs hand you a scenario ("consumer incomes fall," "the price of a complement rises," "the population of buyers grows") and ask what happens to the demand curve and the resulting equilibrium price and quantity. FRQs ask you to draw a correctly labeled supply and demand graph, shift demand in the right direction, and show the new equilibrium. Your job is twofold. First, decide whether the scenario is an INSECT factor (shift the curve) or a price change (move along the curve). Second, get the direction right, which means knowing wrinkles like normal versus inferior goods for the Income shifter.
A change in demand (any INSECT factor) shifts the entire curve, so quantity changes at every price. A change in quantity demanded happens only when the good's own price changes, and it's a movement along a fixed curve. On a graph question, if the cause is price, do not redraw the demand curve. If the cause is income, buyers, substitutes, expectations, complements, or tastes, shift it.
INSECT stands for the six demand shifters: Income, Number of consumers, price of Substitutes, Expectations, price of Complementary goods, and Tastes/preferences.
Price is deliberately not in INSECT because a price change causes movement along the demand curve, not a shift of it.
Any INSECT change shifts the entire demand curve, meaning a different quantity is demanded at every price level.
Income works in opposite directions depending on the good: rising income increases demand for normal goods but decreases demand for inferior goods.
A higher price of a substitute increases demand for your good, while a higher price of a complement decreases it.
This shift-versus-movement logic repeats in every later graph in AP Macro, including aggregate demand in Unit 3.
Income, Number of consumers, Substitutes (their price), Expectations of future prices or income, Complementary goods (their price), and Tastes/preferences. These are the six determinants that shift the demand curve, covered in Topic 1.4.
No. A change in a good's own price causes a movement along the demand curve (a change in quantity demanded), per the law of demand in EK MKT-2.A.1. Only the six non-price INSECT factors shift the curve itself.
A change in demand is a shift of the whole curve caused by an INSECT factor like income or tastes. A change in quantity demanded is a slide along the existing curve caused only by a change in the good's own price. Mixing these up is the most common graphing error on Unit 1 questions.
No. Higher income increases demand for normal goods but decreases demand for inferior goods (like instant ramen or generic brands), where people buy less as they get richer. Exam questions love testing this exception.
No, INSECT is a study mnemonic, not official CED vocabulary. The exam tests the concept behind it, learning objective 1.4.C, by giving you a scenario and asking which way the demand curve shifts and what happens to equilibrium price and quantity.