LECTURE 7 Flashcards
How does commodity tax distort consumer choice?
But affecting relative prices and causing demand to switch from one good to another.
Also affect total consumption/saving.
How do taxes affect consumer and producer prices?
drive a wedge between the 2
What type of tax is commodity tax usually? What does this mean?
Proportional, not lump sum = DISTORTIONARY
How does commodity tax affect IC/BC diagram?
BC PIVOTS INWARDS for good the tax is levied on.
Change in slope of BC.
EQUIVALENT VARIATION asks…
How much money would the consumer be WTP in advance to avoid the tax and be at constant original (pre-tax) prices?
i.e. How much does income need to change before the tax such that utility is equal to the level if the tax is implemented?
EV what hypothetical BL do we draw?
Draw BC parallel to OLD BC and tangent to NEW IC.
- At original prices
- Utility the same level as under the tax.
- Consumers WTP this amount of income shift that brings utility no lower than that under the tax.
How do we calculate EV? What does it tell us?
EV = difference in income the original and hypothetical BLs represent. It tells us the $ value of the welfare loss of the price change induced by the tax.
Whats IE and SE with commodity tax on good 1?
IE: decreased disposable income = reduce consumption of both goods.
SE: good 1 relatively more expensive = substitute 2 for 1.
How do we show a lump sum tax on the same diagram that generates the SAME revenue as the commodity tax?
Draw BL parallel to original BC (no change in prices) that goes through the final commodity tax bundle (ensures generates same revenue)
How can we compare welfare effects of commodity tax and equivalent lump sum?
Lump sum = reaches higher IC
EV higher for commodity tax than lump sum
How do we define DWL of a commodity tax?
The welfare loss (measured in monetary terms) created by the commodity tax over and above the tax revenue generated.
DWL calculation in monetary units
DWL = EV(commodity) - EV(lump sum) DWL = EV(commodity) - tax revenue
How else can we calculate DWL apart from using EV?
Simple demand and supply diagram: DWL = change in CS + PS + government revenue
2 other words for DWL
excess burden / deadweight burden
Uniform tax rates for all goods are NOT optimal if…
consumer has different PED for the goods.
Ramsey optimal tax rule
Optimal tax rates where marginal DWL for the last $1 of tax collected is the SAME across all goods.
Does the Ramsey rule consider both efficiency and equity?
only efficiency - assume just 1 consumer so abstract from redistribution.
How does inverse elasticity rule relate to Ramsey rule? What assumption does it make?
It’s a simplified version of ramsey rule.
Assumes NO CROSS PRICE EFFECTS: demand for a good depends on own price only.
after tax price =
qi = pi + ti
IER BC for 2 goods
q1x1 + q2x2 = wL = L for w=1
What do we assume about individuals? Implication
Assume all individuals are homogenous = we can optimise for one representative individual/
Lagrangian for consumer optimisation
L = U(x1, x2, L) + alpha(L - q1x1 - q2x2)
What Lagrange Multiplier do we use for consumer optimisation?
alpha
3 FOCs for IER consumer optimisation
MU of consumption = lagrange multiplier * after-tax price for both goods.
MU of labour hours = - lagrange multiplier
For consumer IER optimisation, what does alpha represent?
alpha= shadow price = MU of income i.e. change in utility if income rises by $1
Gov revenue constraint in terms of p and q
R = t1x1 + t2x2
ti = qi - pi
R + p1x1 + p2x2 = q1x1 + q2x2
How does the gov obtain t*?
Maximise representative consumer’s utility while satisfying their revenue constraint
What are the government’s choice variables? Why?
x1 and x2
cannot choose L - this is endogenously determined from individual BC once x1 and x2 chosen.
What Lagrange Multiplier do we use for gov optimisation? What does it measure?
lambda = MU of income for the government