1.4 Price change and Welfare Flashcards
(84 cards)
From 1.1-1.3 what have we explored?
In 1.1 - 1.3 we explored how to find uncompensated demand, compensated
demand and the expenditure function
What will we do today?
examine the welfare effects of price changes
What are price indices?
A price index is a number whose movement reflects movement in the average level of prices
In the economy we know prices are changing at different weights so what do we want?
we want a weighted average of price changes, due to this votality of price. This will be a price index
What are the different price indicies in the uk?
CPI ( now the standard)
CPIH ( Consumer price index including owner occupiers housing costs)
RPI ( retail price index)
What is CPI?
Measures the change in the cost of a representative basket of goods and services bought by households
• Interpreted as a measure of how the cost of the standard of living is changing.
Official inflation target is 2%
Compares baskets quarterly, annually.
What is Consumer Prices Index including owner occupiers’ housing costs (CPIH)
Extends CPI to include a measure of the costs associated with owning, maintaining and living in one’s own home.
• OOH costs and Council Tax are significant expenses for many households
What is CPI an example of?
A base weighted index. ( It has a base year, were we draw comparisons from.
Define a base-weighted price index
A weighted average of prices or quantities, where the weights used are the quantities or the prices of the base period.
We are going to show the base weighted price index mathematically?
How do we show a representative consumer basket of n goods at date A and prices of the goods at date A.
Now show the mathematically representation of the prices when we look a year late and then show the base weighted price index?
Its essentiallty prices of same bundle at later date/prices of bundle at earlier date.
We are assuming the bundle is fixed, we are going focusing on prices.
What are some critiques of CPI?
1) The CPI does not take into account the real possibility that consumers would substitute among commodities because of changes in relative prices (cheaper product you buy more) . Substitution bias. Hence it overstates the inflation rate.
2) No representative consumer, there are different segments of consumer reflecting different basket of goods.
If income changes in line with the base weighted price index, then: A. Consumers are neither better off nor worse off B. Consumers cannot be worse off, but may be better off C. Consumers cannot be better off, but may be worse off D. Consumers will definitely be better off
B
If income changes in line with the base weighted price index, then: A. Consumers are neither better off nor worse off B. Consumers cannot be worse off, but may be better off C. Consumers cannot be better off, but may be worse off D. Consumers will definitely be better off
We are going to analyse why b is the answer. So suppose there are 2 goods, how does the CPI base weighted price index look like?
If income changes in line with the base weighted price index, then: A. Consumers are neither better off nor worse off B. Consumers cannot be worse off, but may be better off C. Consumers cannot be better off, but may be worse off D. Consumers will definitely be better off
We are going to analyse why b is the answer. Now show the prices and bundle consumers pick before changes in price and after price change and the utlitiy they get?
What does it mean if income changes at the same rate as the base weighted priced index
This means you can afford the original basket but wil lyou prefer the original basket?
It depends on what happens to prices individually( relative prices, subsistution effect) so the bundle is affordable but not optimal.
Now what is subsitution bias?
if consumers change their purchasing behavior in response to relative price changes. (• If relative prices p1/p2(increase in price of good 1 > increase in price of good 2) change and substitution is possible then the
consumer is better off!)
If income increases at the same rate as the base weighted price index
then the consumer cannot be worse off
To show why a consumer cannot be worse off if income changes at the same rate as the base weighted price index, draw the original budget line and graph and show optimal point?
1) Construct the budget line, with 2 goods?
PART 2) To show why a consumer cannot be worse off if income changes at the same rate as the base weighted price index,
Now suppose prices change but also income at the same rate so P1bX1a + P2bX2a =m. Lets imagine the price of good 1 rose higher than good 2 e.g. good 1 is fuel and it rose by 4% and good 2 rose by 2% but average so CPI went up by 3% , and income goes up by 3%. Show what happens to budget line. What what does it show about being worse off?
The budget line becomes steeper as prices of both goods have increased ( become steeper).
It still goes through bundle A because you can still afford (x1A,x2A). Thus cannot be worseoff.
Will the consumer pick bundle A, if he/she income rises at the same ratio as CPI (3%) increases, and he negotiates a 3% increase at work?
Draw where optimal consumption would be and explain what it shows about CPI?
This will show for individuals, CPI basket of goods are not constant, here substation effects causes you to buy the cheaper thing (x2). Thus as we saw last week to get same utility, your overall inflation is <3% but CPI overstate it to 3%.( due to subsitution effects because of changes in relative price, CPI is an overestimate, as the bundle of goods are fixed, but actually they change)
Are consumers always better off when there is an iincrease in income in line with an increase in CPI? ( remember relative prices change, 1 is the same as the other)
No is the answer, it depends whether or not there is a subsitution effect of not. so perfect complements there will be no change in allocation.
If PC if income rises higher than CPI or just rises, then they will be better off.
What happens if prices rise ( e.g. good 1 and 2 rise by 3% at the same rate as income so 3%?
The budget line stats the same, this is because it is homogeneous to degree 0
or
The BL intercepts are m/p1 and m/p2 so an increase in both as no change BlA = BLb ( consumers are no better off or worse off)
So in summary we line wages, income etc to inflation to get away from harmful effects of inflation ( CPI increases) but whats the problem of this use the example previously?
Subsitution bias can make people better off e.g. if you give a rise in income, to someone who experiences a relative price change with 3% overall( price changes different for the 2 goods,) they might substitute away and be better off. THUS THERE IS OVER COMPENSATION.