The article looks at whether trade policies that give special benefits to certain countries actually help those countries sell more goods to the European Union. The researchers analyzed detailed data using a special model. They found that these preferential trade policies do make a difference in how much stuff gets traded, especially in specific industries. The way they defined the benefits given to these countries also affected how big the impact was. Overall, preferential trade deals boost exports, but the effect varies depending on which sector we're talking about.