The article looks at how the productivity of businesses in New Zealand is affected by the density of the areas they are located in. By studying data from 1999 to 2006, the researchers found that areas with higher density have firms with higher productivity. Specifically, a 10 percent increase in density leads to a 0.69 percent increase in productivity. This shows that businesses benefit from being in areas with more people and resources nearby. The study also looked at how this relationship varies across different industries and regions, and how it interacts with factors like capital and labor.