Changes in trade policy can impact a country's economy through terms-of-trade and volume-of-trade effects. Moving towards global free trade could increase world economic welfare by combining all nations' trade efficiency effects. The debate lies in the significance of terms-of-trade effects. Some studies suggest that in certain cases, the benefits of free trade outweigh the need for transfers, while in others, terms-of-trade gains can make up a substantial portion of a country's benefits from free trade, potentially requiring large transfers.