The article explores how free trade agreements between ASEAN countries and individual partners affected trade over the past 20 years. By looking at trade data and using a method called the gravity trade model, researchers discovered that the agreement with China led to significantly higher trade boosts compared to agreements with Korea and Japan. They found that these agreements generally decreased trade with non-member countries as expected. The imbalance between normal and preferential tariff rates likely contributed to the larger trade improvements seen with China compared to Korea and Japan.