The researchers analyzed the impacts of preferential trading deals using detailed economic models. They found that countries outside such agreements typically lose out, and market access plays a big role in the benefits. Lowering external tariffs can make a weak deal more appealing. In North-South agreements, Southern countries benefit from more competition in their markets without significant price increases from the North. Overall, global gains from broad trade liberalization are higher than gains from regional deals. Countries with low trade barriers benefit more from group agreements than going solo. Requiring tax changes can limit good trade partnerships, and trade taxes aren't the best way to collect revenue. Trade openness tends to help poorer countries overall, but impacts on individual households vary, so safety nets are crucial. The researchers don't expect that time will reverse the benefits of regional trade integration.