The article explores how including different types of companies in trade models can change the results. By comparing two models, one simple and one more complex, the researchers found that when trade barriers are lowered, not only do more companies start exporting, but there are also changes in which industries produce what and how much money different types of workers make. This means that when trade is made easier, it doesn't just help individual companies, but can also affect entire industries and the people who work in them.