Price elasticity of demand is defined as how demand changes as a result of a change in price. It can be said that if a reduction in price leads to an increase in demand then demand is relatively elastic. Elasticity is usually negative. There is an alternative scenario where demand will increase as price does so too. This happens only in the case of Giff en goods, where elasticity is positive. The formula for price elasticity of demand is: Percentage Change in Quantity Demanded Percentage Change in Price One determinant of price elasticity is the number and closeness of substitutes there are available for a good.
The closer the goods are, the greater will be the price elasticity of demand of that good. The reason for this being that people will be able to switch to the substitutes when the price of the original good goes up. The greater the number of substitutes and the closer they are, the more people will be able to switch, and so the bigger the substitution effect will be of any price rise. Another determinant is the proportion of income spent on the good.
The higher the proportion of our income that is spent on a good, the more we will forced to cut back consumption in the event of a price rise, so the bigger the income effect and the more elastic the demand will be. This is the reason salt has a very low price elasticity of demand. We spend such a small proportion of income on salt that a relatively big percentage increase in the price of salt is borne by us without too much difficulty, so the income effect would be pretty small. One other determinant of price elasticity of demand is the time period. When prices rise people may take time to adjust their consumption patterns and find alternatives. The longer the time after a price change, then, the more elastic is demand likely to be.
Income elasticity is a measure of responsiveness of the demand to a change in incomes. Income elasticity is important to firms considering the future market for their product. If the product has a high income elasticity of demand then sales are likely to expand rapidly as national income goes up, but also fall quickly should the economy move into recession. The formula for income elasticity of demand is: Percentage Change in Quantity Demanded Percentage Change in Income One of the determinants of income elasticity of demand is the degree of necessity of the good. In a developed country, the demand for luxury goods expands rapidly as people’s incomes rise, whereas the demand for basic goods, such as bread, only rises a little. So items like cars have a high income elasticity of demand, whereas items like potatoes have a low income elasticity of demand.
For inferior goods, the quantity of goods demanded actually decreases as income goes up. This is true in cases of things like cheap margarine. As people earn more they switch to butter or better quality margarine. Inferior goods have a negative elasticity of demand. The rate at which the desire for the good is satisfied as consumption increases is also a determinant of income elasticity of demand.
The more quickly people become satisfied, the less their demand will rise as income increases. The level of income of the consumers is the last determinant factor of income elasticity of demand. Poor people will behave differently, in the event of a rise income, to a rich person. For example, for a given rise in income, a poor person may buy a lot more butter whereas a rich person might only buy a little bit more. Cross Price elasticity of demand is a measure of the responsiveness of demand for one product to a change in the price of a complement or substitute good. The formula for cross elasticity of demand is: Percentage Change in Demand for Good x Percentage Change in Price of Good y If good y is a substitute for good x, x’s demand will rise as y’s price rises.
Cross elasticity of demand will be positive in this case. If y is a complement to good x, then x’s demand will fall as y’s price rises. Cross elasticity of demand will be negative in this case. The major determinant of cross elasticity of demand is the closeness of the substitute or complement.
The closer it is, the bigger will be the effect on the first good of change in the price of the substitute or complement, and so the greater the cross elasticity. Firms would want to know the cross elasticity of demand for their product when considering the effect on the demand for their product of a change in the price of a rival’s product or of a complementary product. These are vital to firms when making their production plans. Due to the fact that rail fares are relatively price inelastic, a small rise in the price of a ticket would not seriously affect the number of people travelling by train in the United Kingdom.
This is because only a very small proportion of our income is spent on train tickets, so a big percentage rise in the cost of a ticket is borne by us without too much difficulty. However, as the road network of the United Kingdom cover a vaster expanse of land than the rail network does, sometimes coach travel is the only alternative to the car. Cross elasticity of demand for coaches in these areas will be zero. In places served by both road and rail networks, coach travels demand will probably be greater, even though it probably makes less financial sense.
This is because sometimes people prefer a private coach with people they know than public transport. Also, a coach will take you to the exact destination you want to go to, but a train will only take you to the station and you must make your own way to the place. As the average national salary is now at a high level, people may be able to afford cars, so this may discourage the use of rail and coach transport. However, in some cases it may cheaper to use a coach than many cars, for example a day trip to the seaside. In the short run, it may be more appropriate to use rail transport, whatever the increase in rail fares. This is because any other form of transport would require a significant amount of investment.
A coach may not be suitable for daily journey’s to work, but may be better suited to long, occasional journey’s like visits to museums. The relatively little fare may not seem to big a burden on your finances. However, when looked at in a group, you may fond that rail transport is more expensive than collectively hiring a coach and going to your destinations in that. In the long term it may be cheaper to buy a car than use road or rail transport, as the money saved by using the car would eventually cover the costs of buying and maintaining the car. A big increase in rail fare may not have the same effect though. It may be cheaper to hire a coach in the short term, so collectively you may hire a coach, but it may also be that car transport is even cheaper than these in both the long and short run, so you may find yourself driving to work instead of using the train.
The price elasticity of rail transport is fairly inelastic, so it may be cheaper to just use the car from the start. The cross elasticity’s of the coach and rail transport may be high in some places and low in others, so it may be pointless limiting yourself to one type transport as it will simply pile on the costs. The income elasticity of the coach is very high, so even a little increase may pinch your pocket a little too hard.