Comparing Import Protection With Export Promotion

Why Compare Trade Policies?

A government that wants to support a domestic industry can restrict imports or encourage exports. These policies may both raise the price received by domestic producers, but they do not necessarily have the same effects on consumers, trade volumes, public finances, or national welfare. Comparing them requires tracing each effect rather than treating “support for domestic production” as a single outcome.

The analysis here uses the small-country model: the country takes the world price as given, and its policy does not change that price. Markets are competitive, the good is homogeneous, and there are no externalities or other market failures. The welfare accounting includes domestic consumer surplus, domestic producer surplus, and government revenue or spending. It excludes distributional judgments and administrative costs. Where a quota creates rents, the analysis states who receives them.

Definition: An import tariff is a tax on each unit imported. An import quota is a binding limit on the quantity imported. An export subsidy is a government payment for each unit exported. Consumer surplus measures buyers’ gains above the price they pay; producer surplus measures sellers’ gains above the minimum price at which they would supply. National welfare in this model is consumer surplus plus producer surplus plus government revenue, less government spending.

A tariff and a binding quota can both raise the domestic price above the world price and reduce imports. An export subsidy works in the opposite direction for trade: it encourages exports, and in the small-country model it raises the domestic price above the world price. The details of the policy determine whether the government collects revenue, spends funds, or creates quota rents.

Effects of Import Protection

With free trade, the domestic price equals the world price. At that price, domestic demand and supply determine imports: imports equal quantity demanded minus quantity supplied, when demand exceeds supply. A tariff raises the domestic price by the tariff amount in the small-country model, provided imports continue. The higher price reduces domestic consumption, increases domestic production, and reduces imports. The government collects tariff revenue on the units that remain imported.

A binding quota fixes imports at a specified quantity. Its domestic price is the price at which domestic demand less domestic supply equals the quota. The gap between that price and the world price creates quota rent on each imported unit. If domestic firms or residents receive the licenses, that rent remains a domestic benefit. If foreign exporters receive it, it is not part of domestic national welfare.

Worked Example: A Tariff and an Equivalent Import Quota

Suppose domestic demand and supply are $Q_D=180-2P$ and $Q_S=2P+20$, where price $P$ is in dollars per unit and quantities are units per period. The world price is $P_W=\$30$. Compare free trade with a tariff of $\$5$ per imported unit, then identify a quota with the same market outcome. Assume the tariff does not eliminate imports.

Free-trade outcome. At $P=\$30$, demand is $Q_D=180-2(30)=120$, and supply is $Q_S=2(30)+20=80$. Imports are $120-80=40$ units.

Tariff outcome. The domestic price is $\$30+\$5=\$35$. Demand is $180-2(35)=110$, and supply is $2(35)+20=90$. Imports are $110-90=20$ units. Tariff revenue is $\$5(20)=\$100$.

Surplus changes. The price rises by $\$5$, while demand falls from 120 to 110 units. The consumer-surplus loss is the area of a trapezoid: $\$5(120+110)/2=\$575$. Supply rises from 80 to 90 units, so the producer-surplus gain is $\$5(80+90)/2=\$425$. National welfare changes by $-\$575+\$425+\$100=-\$50$.

Equivalent quota. A quota of 20 imported units produces the same price and quantities in this model: at $\$35$, excess demand is $110-90=20$. The quota rent is $(\$35-\$30)(20)=\$100$. If domestic license holders receive it, national welfare changes by $-\$575+\$425+\$100=-\$50$, matching the tariff. If foreign exporters receive the rent, national welfare changes by $-\$575+\$425=-\$150$. The $\$100$ difference is the rent that leaves the country.

Method and trap avoided. Calculate the price and quantities first, then calculate the policy’s revenue or rent and include it only if it accrues domestically. A common mistake is to count quota rent as domestic welfare without checking who holds the import licenses.

Effects of Export Promotion

In the small-country model, an export subsidy of $s$ dollars per unit raises the domestic price to $P_W+s$ when the policy leads to positive exports and arbitrage links the domestic and export markets. At that higher price, domestic producers supply more and domestic consumers demand less. Exports therefore rise. The government’s fiscal cost is the subsidy per exported unit multiplied by the number of exported units.

The producer gain does not by itself establish a welfare gain. Consumers lose from the higher domestic price, and taxpayers fund the subsidy. The following example illustrates why all three parts of the accounting matter, including when free trade initially produces no exports.

Worked Example: An Export Subsidy When Free Trade Starts at No Trade

Use $Q_D=180-2P$ and $Q_S=2P+20$, with a world price of $\$40$ per unit. The government introduces an export subsidy of $\$10$ per exported unit. Assume the small-country conditions above and that the subsidy results in positive exports.

Before the subsidy. At $P=\$40$, demand is $180-2(40)=100$, and supply is $2(40)+20=100$. Exports are $100-100=0$. Thus there is no subsidy spending before the policy.

After the subsidy. The domestic price is $\$40+\$10=\$50$. Demand is $180-2(50)=80$, and supply is $2(50)+20=120$. Exports are $120-80=40$ units. Government spending is $\$10(40)=\$400$.

Surplus changes. Consumers pay $\$10$ more, and their quantity falls from 100 to 80. Their surplus falls by $\$10(100+80)/2=\$900$. Producers receive $\$10$ more, and their quantity rises from 100 to 120. Their surplus rises by $\$10(100+120)/2=\$1{,}100$. Subtracting the subsidy cost gives a national welfare change of $-\$900+\$1{,}100-\$400=-\$200$.

Check. The producer gain exceeds the consumer loss by $\$200$, but the government spends $\$400$. The net change is therefore a loss of $\$200$. This is consistent with the two efficiency losses created by the policy: resources shift toward excess production, and domestic consumption is reduced.

Method and trap avoided. Use the stated world price throughout and calculate exports after the subsidy from domestic supply minus domestic demand. Do not substitute another world price or assume that the initial export quantity was positive: here it is zero, while the post-subsidy export quantity is 40.

Why Tariff Deadweight Loss Has a Triangle Form

A short derivation clarifies the welfare comparison. Suppose the tariff raises price by $t$, from $P_W$ to $P_W+t$, and imports remain positive. Let $Q_D^0,Q_S^0$ be demand and supply at the world price, and $Q_D^1,Q_S^1$ be demand and supply at the tariff price. With linear demand and supply, the consumer-surplus loss is the price increase times average demand across the two prices. The producer-surplus gain is the same calculation using supply.

\begin{aligned} \text{Consumer loss} &= t\frac{Q_D^0+Q_D^1}{2},\\ \text{Producer gain} &= t\frac{Q_S^0+Q_S^1}{2},\\ \text{Tariff revenue} &= t(Q_D^1-Q_S^1). \end{aligned}

Subtract the consumer loss from the producer gain and add tariff revenue. Since imports at the tariff price equal $Q_D^1-Q_S^1$, the terms associated with the quantities remaining in the market cancel:

\begin{aligned} \Delta W &=-t\frac{Q_D^0+Q_D^1}{2} +t\frac{Q_S^0+Q_S^1}{2} +t(Q_D^1-Q_S^1)\\ &=-\frac{t}{2}\big[(Q_D^0-Q_D^1)+(Q_S^1-Q_S^0)\big]. \end{aligned}

The quantity changes in the last expression are nonnegative: demand falls and supply rises as price increases. The expression is the negative of the two triangles associated with reduced consumption and expanded domestic production. This result applies to the stated linear, small-country setting with a tariff that leaves imports positive; it is not a general formula for cases involving nonlinear curves, changing world prices, or other market distortions.

Key result: In the small-country model, a tariff’s revenue is a transfer to the government, not a resource loss. The deadweight loss comes from the units no longer consumed and the additional units produced domestically. For an equivalent quota, the corresponding price gap creates quota rent; whether that rent counts in national welfare depends on who receives it.

Comparing the Three Instruments

Instrument	Domestic price and quantities	Public budget or rent	Welfare consideration
Import tariff	Price rises; domestic production rises; consumption and imports fall	Government collects tariff revenue on imports	Revenue offsets part of the surplus losses; production and consumption distortions remain
Import quota	A binding limit raises price; production rises; consumption falls; imports equal the limit	Creates quota rents on imported units	Like tariff revenue if rents stay domestic; a greater domestic loss if rents go abroad
Export subsidy	Price rises; production and exports rise; domestic consumption falls	Government spends on each exported unit	Producer gains must be weighed against consumer losses and fiscal cost

The instruments can have similar price effects but different fiscal and rent consequences. In particular, a tariff raises revenue, while an export subsidy requires public spending. A quota can resemble a tariff in price and quantity effects, but its rent does not automatically accrue to the government or to domestic residents.

Quota Rents and National Welfare

The ownership of quota licenses can change the national-welfare calculation even when the domestic price, domestic quantities, and import limit are unchanged. The next example separates the surplus changes from the location of the rent.

Worked Example: A Quota Whose Rent Goes Abroad

Domestic demand is $Q_D=160-2P$, and domestic supply is $Q_S=P+10$. The world price is $\$30$, and the government imposes a quota limiting imports to 30 units. Assume foreign exporters receive all quota rents.

Free trade. At $\$30$, demand is $160-2(30)=100$ units and supply is $30+10=40$ units. Imports are $100-40=60$ units.

Quota price and quantities. At the quota equilibrium, excess demand equals 30: $160-2P-(P+10)=30$. Rearranging gives $150-3P=30$, so $P=\$40$. Demand is $160-2(40)=80$, supply is $40+10=50$, and imports are $80-50=30$, as required.

Surplus and rent. The price rises by $\$10$, and demand falls from 100 to 80, so consumer surplus falls by $\$10(100+80)/2=\$900$. Supply rises from 40 to 50, so producer surplus rises by $\$10(40+50)/2=\$450$. Quota rent is $(\$40-\$30)(30)=\$300$, but it goes to foreign exporters and is not a domestic benefit. National welfare therefore changes by $-\$900+\$450=-\$450$.

Check and method. Of the $\$450$ national loss, $\$300$ is quota rent received abroad and $\$150$ is deadweight loss. The check is $\$300+\$150=\$450$. The common error is to report only the foreign rent as the national loss; that omits the additional domestic efficiency loss.

Common Comparison Traps

Ignoring the policy’s fiscal side. Count tariff revenue as a domestic benefit and export-subsidy spending as a domestic cost in this model.
Assuming quota rent belongs to the government. A quota creates a price gap, but the recipient depends on license allocation.
Confusing a higher producer price with a welfare gain. Producer surplus is only one component of national welfare.
Using a world-price change in a small-country calculation. The world price is fixed by assumption; the policy changes the domestic price.
Forgetting the trade balance in quantities. Imports equal domestic demand minus supply; exports equal supply minus demand. Check the sign before calculating revenue or subsidy spending.

These comparisons are aligned with the SOA VEE Economics (Validation by Educational Experience) syllabus. The central habit is to keep the model assumptions visible, calculate prices and quantities before welfare, and identify who receives any policy-generated revenue or rent.

Check Your Understanding

For each problem, use the stated small-country assumptions and show the price, quantity, and welfare steps before checking the final answer.

Demand is $Q_D=240-2P$, supply is $Q_S=2P$, and the world price is $\$50$. A tariff of $\$5$ is imposed. Find post-tariff demand, supply, imports, tariff revenue, and the national-welfare change. (Answer: $Q_D=130$, $Q_S=110$, imports $=20$, revenue $=\$100$, welfare change $=-\$50$.)
Demand is $Q_D=140-2P$, supply is $Q_S=P$, and the world price is $\$20$. A quota limits imports to 50 units. Find the domestic price and quota rent. Then find the welfare change if the rent goes to domestic license holders and if it goes to foreign exporters. (Answer: price $=\$30$, rent $=\$500$; welfare change $=-\$150$ with domestic rents and $-\$650$ with foreign rents.)
Demand is $Q_D=140-2P$, supply is $Q_S=2P$, and the world price is $\$35$. An export subsidy of $\$5$ per unit is introduced. Find exports and subsidy spending after the policy, then calculate the national-welfare change. (Answer: post-subsidy price $=\$40$, demand $=60$, supply $=80$, exports $=20$, spending $=\$100$, welfare change $=-\$50$.)
A tariff and an import quota produce the same domestic price and reduce imports by the same amount. State one condition under which their national-welfare effects match and explain why the answer can differ if that condition fails. (Answer: They match when quota rents remain domestic and equal the tariff revenue; if rents go abroad, domestic welfare is lower by the rent transferred abroad.)

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