1. Demand and Supply Analysis

2. Demand Demand: effective desire
Demand is that desire which backed by willingness and ability to buy a particular commodity.
Amount of the commodity which consumers are willing to buy per unit of time, at that price.
Things necessary for demand:
Time
Price of the commodity
Amount (or quantity) of the commodity consumers are willing to purchase at the price

3. Types of Demand Direct and Derived Demand
Direct demand is for the goods as they are such as Consumer goods
Derived demand is for the goods which are demanded to produce some other commodities; e.g. Capital goods
Recurring and Replacement Demand
Recurring demand is for goods which are consumed at frequent intervals such as food items, clothes.
Durables are purchased to be used for a long period of time
Wear and tear over time needs replacement
Complementary and Competing Demand
Some goods are jointly demanded hence are complementary in nature, e.g. software and hardware, car and petrol.
Some goods compete with each other for demand because they are substitutes to each other, e.g. soft drinks and juices.

4. Determinants of Demand
Price of the product
Single most important determinant
Negative effect on demand
Higher the price-lower the demand
Income of the consumer
Normal goods: demand increases with increase in consumer’s income
Inferior goods: demand falls as income rises
Price of related goods
Substitutes
If the price of a commodity increases, demand for its substitute rises.
Complements
If the price of a commodity increases, quantity demanded of its complement falls.

5. Determinants of Demand
Contd…
Tastes and preferences
Very significant in case of consumer goods
Expectation of future price changes
Gives rise to tendency of hoarding of durable goods
Population
Size, composition and distribution of population will influence demand
Advertising
Very important in case of competitive markets

6. Demand Function
Interdependence between demand for a product and its determinants can be shown in a mathematical functional form
Dx = f(Px, Y, Py, T, A, N)
Independent variables: Px, Y, Py, T, A, N
Dependent variable: Dx
Px: Price of x
Y: Income of consumer
Py: Price of other commodity
T: Taste and preference of consumer
A: Advertisement
N: Macro variable like inflation, population growth, economic growth

7. Law of Demand
A special case of demand function which shows relation between price and demand of the commodity
Dx = f(Px)
Other things remaining constant, when the price of a commodity rises, the demand for that commodity falls or when the price of a commodity falls, the demand for that commodity rises.
Price bears a negative relationship with demand

8. Demand Schedule and Individual Demand Curve10 20 30 15 35 50 40 25
Quantity of coffee
Price of Coffee O
Point on Demand Curve
Price (Rs per cup)
Demand (‘000 cups) a 15 50 b 20 40 c 25 30 d e 35 10 e d c b a

9. Shift in Demand Curve Shift in demand curve from D0 to D1
More is demanded at same price (Q1>Q)
Increase in demand caused by:
A rise in the price of a substitute
A fall in the price of a complement
A rise in income
A redistribution of income towards those who favour the commodity
A change in tastes that favours the commodity
Shift in demand curve from D0 to D2
Less is demanded at each price (Q2<Q) D0
Price
Quantity D1 D2 P Q2 Q Q1

10. Exceptions to the Law of Demand
Law of demand may not operate due to the following reasons:
Giffen Goods
Snob Appeal
Demonstration Effect
Future Expectation of Prices (Panic buying)
Addiction
Neutral goods
Life saving drugs
Salt
Amount of income spent
Match box

11. Market Demand
Market: interaction between sellers and buyers of a good (or service) at a mutually agreed upon price.
Market demand
Aggregate of individual demands for a commodity at a particular price per unit of time.
Sum total of the quantities of a commodity that all buyers in the market are willing to buy at a given price and at a particular point of time (ceteris paribus)
Market demand curve: horizontal summation of individual demand curves

12. Supply
Indicates the quantities of a good or service that the seller is willing and able to provide at a price, at a given point of time, other things remaining the same.
Supply of a product X (Sx) depends upon:
Price of the product (Px)
Cost of production (C)
State of technology (T)
Government policy regarding taxes and subsidies (G)
Other factors like number of firms (N)
Hence the supply function is given as:
Sx = (Px, C, T, G, N)

13. Supply (‘000 cups per month)
Law of Supply
Law of Supply states that other things remaining the same, the higher the price of a commodity the greater is the quantity supplied.
Price of the product is revenue to the supplier; therefore higher price means greater revenue to the supplier and hence greater is the incentive to supply.
Supply bears a positive relation to the price of the commodity.
Supply Schedule
Supply Curve 30 10 20 60 50 40 15 35 25
Price of Coffee
Quantity of Coffee
Point on Supply Curve
Price (Rs. Per cup)
Supply (‘000 cups per month) a 15 10 b 20 c 25 30 d 45 e 35 60 e d c b a

14. Change in Supply Shift in the supply curve from S0 to S1
More is supplied at each price (Q1>Q0)
Increase in supply caused by:
Improvements in the technology
Fall in the price of inputs
Shift in the supply curve from S0 to S2
Less is supplied at each price (Q2<Q0)
Decrease in supply caused by:
A rise in the price of inputs
Change in government policy (VAT) S0
Price
Quantity O S2 S1 P Q0 Q2 Q1

15. Market Equilibrium
Equilibrium occurs at the price where the quantity demanded and the quantity supplied are equal to each other.
At point E demand is equal to supply hence 25 is equilibrium price
Quantity
Price O
Price
(Rs)
Supply
(‘000 cups/ month)
Demand (‘000 cups/ month) 15 10 50 20 40 25 30 45 35 70 D S 25 E 30

16. Market Equilibrium
For prices below the equilibrium, Quantity demanded exceeds quantity supplied (D>S)
Price pulled upward
For prices above the equilibrium, Quantity demanded is less than quantity supplied (D<S)
Price pulled downward.
At point E demand is equal to supply hence 25 is equilibrium price. D S
Quantity
Price O
Price
(Rs)
Supply
(‘000 cups/ month)
Demand (‘000 cups/ month) 15 10 50 20 40 25 30 45 35 70 30 25 E 30 20

17. Changes in Market Equilibrium
(Shifts in Supply Curve)
The original point of equilibrium is at E, the point of intersection of curves D1 and S1, at price P and quantity Q
An increase in supply shifts the supply curve to S2
Price falls to P2 and quantity rises to Q2, taking the new equilibrium to E2
A decrease in supply shifts the supply curve to S0. Price rises to P0 and quantity falls to Q0 taking the new equilibrium to E0
Thus an increase in supply raises quantity but lowers price, while a decrease in supply lowers quantity but raises price; demand being unchanged Q P E D1 S1
Price
Quantity O E0 P0 Q0 S0 S2 Q2 P2 E2

18. Changes in Market Equilibrium
(Shifts in Demand Curve)
The original point of equilibrium is at E, the point of intersection of curves D1 and S1, at price P and quantity Q
An increase in demand shifts the demand curve to D2
Price rises to P1 and quantity rises to Q1 taking the new equilibrium to E1
A decrease in demand shifts the demand curve to D0
Price falls to P* and quantity falls to Q* taking the new equilibrium to E2.
Thus, an increase in demand raises both price and quantity, while a decrease in demand lowers both price and quantity; when supply remains same. D1 S1
Price
Quantity O E P Q D2 D0 Q1 P1 E1 Q* P* E2

19. Change in Both Demand and Supply
Initial equilibrium is at E1, with price quantity combination (P1, Q1).
An increase in both demand and supply takes place;
demand curve shifts to the right from D1 D1 to D2 D2
supply curve also shifts to the right from S1 S1 to S2 S2.
The new equilibrium is at E2, and price quantity is (P2, Q2).
An increase in both supply and demand will cause the sales to rise, but
the price will increase if increase in D>S (as at E2 )
No change in price if increase in D=increase in S (as at E0 ) D2
Quantity
Price O D2 D1 S1 S2 P2 Q2 E2 P1 E1 E0 Q1

20. Summary
Demand is defined as the desire to acquire a commodity to satisfy human wants, which is backed by ability to pay the price.
Categories of demand are made on the basis of the nature of commodity demanded (consumer goods and capital goods); time unit for which it is demanded (short run and long run); relation between two goods (substitutes and complements), etc.
The law of demand states that the consumers will buy more of the commodity when prices are high and less when prices are low, provided all the other factors of demand remains constant.
Demand for a product X (Dx) is a function of price of the commodity X (Px), income of the consumer (Y), price of related (substitutes or complements) commodities (Po), tastes and preference of the consumer (T), advertising (A), future expectations (Ef), population and economic growth (N).
A change in quantity demanded denotes movements along the demand curve due to a change in price, while a change in demand denotes a rightwards or leftward shift of the demand curve due to a change in the other determinants of demand other than price.

21. Summary
Supply is defined as the willingness to produce and sell the commodity by production units or firms.
The law of supply states that firms will sell more of the commodity when prices are high and less of the commodity when prices are low provided all the other factors of supply remains constant.
Supply of a product X (Sx) is a function of price of the product (Px), cost of production (C), state of technology (T), Government policy regarding taxes and subsidies (G), other factors like number of firms (N).
Change in quantity supplied refers to movements along the same supply curve due to change in the price of the commodity. However when change in supply is associated with change in the factors like costs of production, technology, etc. it causes a shift of the supply curve upwards or downwards
Market equilibrium occurs where demand and supply are equal. This equilibrium determines the price in the market through the forces of demand and supply. Comparative statics is the process of comparison between two equilibrium situations.
An increase in both supply and demand will cause the sales to rise, but the effect on price can be positive, negative or equal to zero, depending on the extent of the shifts in the demand and supply curves.