ECES905205 pertemuan 3
2022-09-12
We learned Ricardian model, the earliest of trade model.
gains from trade(in a purely economic sense) comes from specialization and comparative advantage.
This model has strong assumptions: free movement of factor between industry.
2 Sectors i: Cloth (C) and Food (F)
3 factors j: Labor (L), Terrain (T), and Capital (K).
Now that we have 2 factors each industry, we need to rethink our PPF.
Since L is the only moving factor, the only way to increase industrial production is to increase \(L\).
since total number of labour is fixed, the only way to increase \(L\) in one industry is to decrease the other industry’s \(L\)
However, since other factors ain’t moving, we have a diminishing returns to labour.
Imagine your office increase no. of employee but not computers.
Increase no. of farmers but not land.
Meaning, labour productivity (i.e., marginal product of labour, MPL) goes down as \(L_i\) goes up.
Note: F industry is identical.
Another 1 unit of \(L_C\) increases \(Q_C\) by \(MPL_C\) unit.
as \(L_C\) goes up, \(MPL_C\) goes down.
\(Q_C\) will keep increasing albeit in decreasing amount.
As \(L_C\) up by 1 unit, \(L_F\) down by 1 unit.
Consequently, an increase in \(Q_C\) is accompanied by decrease in \(Q_F\).
The rate, however, varies.
\[L_C+L_F=L\]
To increase \(Q_C\) by 1 unit, \(Q_F\) must decrease by \(\frac{MPL_F}{MPL_C}\)
From here, we can express \(Q_C\) as the function of \(Q_F\):
\[ \text{Slope of PPF}=-\frac{MPL_F}{MPL_C} \]
\[ MPL_C \times P_C = w \]
diminishing return leads to a non-linear ppf.
production ended-up at dot 1, where PPF tangents price ratio.
This is a bit different compared to ricardian with a linear PPF and a constant MPL.
4-quadrant grafik is an excellent tool to visualize QF/QC relationship.
The labour market movement depends on MPL of the two industries
An equilibrium exists where \(MPL_i \times P_i\), where employment settles at some level \(w\).
The labour market dynamics changes when MPL or price ratio changes
\(\left(\frac{P_C}{P_F}\right)\).
Note that L is fixed, \(L_C\) is the left one.
Say an inflation leads to both prices increase by 10% \(P_C^*=1.1P_C\) and \(P_F*=1.1P_F\)
With a fixed MPL, increase of both curves \(MPL_i \times P_i\) is in-line with increase in \(P\)s.
Since both prices go up at the same pace, labour dynamics does not change.
Prices up by also 10%, negates the impact of the inflation. No welfare changes.
Let this country trades, and in the global market, \(P_C\) is 10% more expensive while \(P_F\) is the same.
Then price ratio changes, i.e., \(\frac{P_C}{P_F} \uparrow\)
Labour market will shift toward C, where \(L_C \uparrow\) while \(L_F \downarrow\)
Wage goes up, but not as much as increase in \(P_C\).
CHanges in price ratio leads to changes in production allocation.
Remember that production will be done such that its slope equals to price ratio.
When price ratio changes, production allocation follows.
new allocation bear consequences: changes in income distribution.
This is a consequence of disproportional changes: \[ \Delta P_C > \Delta w > \Delta P_F \]
\[ \frac{w}{P_C} < \frac{w}{P_F} \]
Does labour better off? Depends on the preference:
Both receives the same wage
Workers benefit if C is less important in their basket.
However, specific factor owner is decisive:
Capital owners win, Land owners lose.
We can show this from surplus dynamics.
Trade benefits the factor that is specific to the export sector of each country but hurts the factor specific to the import-competing sectors, with ambiguous effect on mobile factors.
Results from trade is ambiguous in this case. Can we show that trade ALWAYS better in general?
Without trade, consumption = production
\[ D_C=Q_C \ and \ D_F=Q_F \]
with trade, consumption does not need to equal production, as long as:
\[ P_C \times D_C + P_F \times D_F = P_C \times Q_C + P_F \times Q_F \]
We can rearrange the budget constraint as such:
\[ D_F - Q_F = \left(\frac{P_C}{P_F}\right) \times (Q_C-D_C) \]
That is, import of F = price ratio times C export.
How much we can import depends on how much we can export.
Without trade, consumption = production = at the PPF.
With trade, we have a bit more option. Of course the option that makes sense is what makes us better off: unambiguously if we can have more of both goods.
As long as the better set is always reachable, compensation is always an option.
With trade, we have option as long as it’s in the budget constraint.
obviously this allocation includes the old set.
the option comes from the ability to export and import.
we can reach allocation even previously unfeasible.
That said, just because everyone CAN benefit doesn’t mean everyone WILL.
International trade can possible make immobile factor owners worse off.
However, this issue isn’t the worse to economists:
income distribution changes happen all the time: tech changes, pandemics, etc.
compensation always better than trade restriction.
In a democratic country, mobilization of the masses is extremely important.
Government intervention happens in concentrated industries.
When cornered, industries will have the same interest thus easier to organize.
Those who benefits from trade usually consumers who are badly organized.
It’s good to note that this model can be seen as a short-run model.
In the long-run, investment will increase the immobile factors: capital accumulations, land reclamations, deforestation, etc.
Factor may moves in the long run:
if mining is sustainably large, people will pursue degrees in mining.
Sell land, buy factories.