The article shows that when markets have more options for similar products, productivity levels become more consistent and higher overall. This happens because lower-cost plants attract more customers, pushing inefficient plants out of business. The study focuses on the concrete industry and how transport costs affect market segmentation. By analyzing local demand, the researchers found that it greatly impacts productivity levels in different regions. Their new method for estimating plant productivity supports these findings, showing that market structure plays a significant role in productivity variations within industries.