ECES905205 meeting 4
2023-09-01
Ricardian: comparative advantage & specialization, everybody happy.
Specific factor: comparative advantage, better in aggregate amid open possibilities / choices.
Both Ricardian and Specific Factor model relies on difference in technologies in explaining why two countries trade.
However, even some countries with the same tech still trade.
In addition to difference in technologies, difference in relative abundance of resources can also drive trade.
Here, we also show how different relative factor intensity drives trade.
\[ \frac{a_{LC}}{a_{KC}} > \frac{a_{LF}}{a_{KF}} \\ \frac{L_C}{K_C} > \frac{L_F}{K_F} \]
\[ \frac{\frac{\partial Q}{\partial K}}{\frac{\partial Q}{\partial L}}=\frac{r}{w} \rightarrow \frac{L}{K}=\omega \left(\frac{w}{r}\right) \]
\(\frac{MP_L}{MP_K} \propto \frac{L}{K} \propto \frac{w}{r} \propto \frac{P_C}{P_F}\)
\[ c_j=wa_{Lj}+ra_{Kj} \]
\[ a_{Kj}=\left(\frac{c}{r}\right)-\left(\frac{w}{r}\right)a_{Lj} \]
In a competitive market, \(p=c\)
F>0 which means:
\[ P_F=a_{LF}(.)w+ a_{KF}(.)r \\ P_C=a_{LC}(.)w+ a_{KC}(.)r \]
Full employment means all capital and labour are exhausted to the two industries.
meaning:
\[ L=a_{LF}(.)F+a_{LC}(.)C \\ K=a_{KF}(.)F+a_{KC}(.)C \]
if the relative price of a good increases, then the real factor price used intensively in the production of that good increases, while the real price of the other factor decreases.
Changes in prices change income distribution between labour and capital owners.
Let \(\frac{P_C}{P_F} \uparrow\) (labor intensive):
\[ P_F=a_{LF}(.)w+ a_{KF}(.)r \\ P_C=a_{LC}(.)w+ a_{KC}(.)r \]
Do a total differentiation. Since \(a_{ij}(.)\) is not a function of output prices, a small change in output price does not change them.
\[ dP_F=a_{LF}(.)dw+ a_{KF}(.)dr \\ dP_C=a_{LC}(.)dw+ a_{KC}(.)dr \]
\[ \frac{dP_F}{P_F}=\frac{a_{LF}(.)}{P_F}dw+ \frac{a_{KF}(.)}{P_F}dr \\ \frac{dP_C}{P_C}=\frac{a_{LC}(.)}{{P_C}}dw+ \frac{a_{KC}(.)}{P_C}dr \] - Multiply with \(\frac{w}{w}\) and \(\frac{r}{r}\)
\[ \frac{dP_F}{P_F}=\frac{a_{LF}(.)w}{P_F}\frac{dw}{w}+ \frac{a_{KF}(.)r}{P_F}\frac{dr}{r} \\ \frac{dP_C}{P_C}=\frac{a_{LC}(.)w}{{P_C}}\frac{dw}{w}+ \frac{a_{KC}(.)r}{P_C}\frac{dr}{r} \]
Then:
\[ \hat{P_F}=\theta_{LF}\hat{w}+\theta_{KF}\hat{r} \\ \hat{P_C}=\theta_{LC}\hat{w}+\theta_{KC}\hat{r} \]
Let cloth price goes up (\(\hat{P_C}>0\)) while food price stays (\(\hat{P_F}=0\))
\[ 0=\theta_{LF}\hat{w}+\theta_{KF}\hat{r} \\ \hat{P_C}=\theta_{LC}\hat{w}+\theta_{KC}\hat{r} \]
It must be the case that one factor increase price while the other goes down.
Remember, C is labour intensive. Meaning:
\[ \frac{\theta_{LF}}{\theta_{KF}}<\frac{\theta_{LC}}{\theta_{KC}} \]
Weight for \(\hat{w}\) is higher in \(C\) than in \(F\). Since \(\hat{P_C}>0\), then it must be the case that \(\hat{w}>0\) and \(\hat{r}<0\).
\[ \hat{w} > \hat{P_C} > 0 > \hat{r} \]
If output prices stay the same and one factor of production increase, then the production of the good that intensive in that factor rises while the production of the good that is not intensive in that factor reduces.
In short, a sudden increase in the abundance of one factor changes income distribution.
\[ \hat{L}=\lambda_{LF}\hat{F}+\lambda_{LC}\hat{C} \\ \hat{K}=\lambda_{KF}\hat{F}+\lambda_{KC}\hat{C} \]
\[ \hat{L}=\lambda_{LF}\hat{F}+\lambda_{LC}\hat{C} \\ 0=\lambda_{KF}\hat{F}+\lambda_{KC}\hat{C} \]
-Since C labor-intensive, then
\(\frac{\lambda_{LC}}{\lambda_{KC}}>\frac{\lambda_{LF}}{\lambda_{KF}}\)
\[ \hat{C}>\hat{L}>0>\hat{F} \]
The country that is abundant in a factor exports the good whose production is intensive in that factor
In general:
Countries tend to export goods whose production is intensive in factors with which the countries are abundantly endowed.
At home, trade benefits labour cuz what they produce by a lot is expensive in the gloal market (\(P_C>P_C^*\)) while they get access to cheaper food (\(P_F>P_F^*\))
For the other side, On the other hand, trade benefits capital owners.
Owners of a country’s abundant factors gain from trade, but owners of a country’s scarce factors lose
Ultimately what we care about is welfare change,
So far, the ultimate goal of trade is that we can acquire more goods by excessively produce goods we good at, import those we bad at.
Therefore, relative price of export and import goods matter a great deal:
Terms of trade \(=\frac{P_X}{P_M}\) which are just price indices of exported and imported goods.
ToT is often used to show welfare changes: Higher number is better, lower number is worse
Note that lower ToT still better than autarky. If it’s worse, we can always return to autarky.
Price indices also subject to change. e.g., Indonesia used to be oil exporter, now net oil importer.
Trade is good thanks to specialization and options to go along the ToT line.
Factor immobility create winners & losers in the short-run.
Factor relative abundance & factor-intensity create winners & losers in the long-run.
The last two creates incentive for losers to ban trade, often enough for losers to act.
But since overall economy still gain, a compensation mechanism makes sense.
To appreciate all of these insights, however, you must understand where this gain come from.
Remember, economic model we uses so far have very specific assumptions:
Price takers in the world market (small country assumption)
Static (no intertemporal consumption & saving)
no barriers to entry (fixed cost is very small)
fixed technology (no learning by doing)
As usual, a government intervention is desirable under the presence of market failures.
Big countries can set prices.
Capital market imperfection.
Large fixed cost as a barrier to entry.
That is, under these setting, an intervention may indeed improve gains over free trade.
Next week we will learn these market failures and trade dynamics.