​Imposing a quota on the import of a good is preferable to a tariff because a tariff creates a deadweight loss while a quota does not.

Deadweight Loss

A loss of economic efficiency that occurs when the equilibrium for a good or a service is not achieved or is not achievable.

Quota

A government-imposed trade restriction that limits the number or monetary value of goods that can be imported or exported during a specific time frame.

Tariff

Tariff is a tax imposed on imported goods and services to regulate trade and to increase government revenue.