The study looked at why factories in Russian cities work more efficiently when they're close to other factories. Researchers studied data from a survey to find out why being near other businesses makes factories more productive. They found that factories in big groups in urban areas have about 17-21% higher worker productivity. This boost comes from factories being close to various types of businesses in the city and the region around it. The study also showed that if a city has good roads and attracts workers from other places, the productivity benefits of being in a group are even greater. It's not just about having a lot of factories together; it's also about having different types of businesses around.