The article looks at why some regions in Spain are becoming more similar in terms of productivity. The researchers used data from different regions in Spain to see if factors like technology, education, and job distribution were making a difference. They found that regions are catching up in technology, education levels are getting more equal, and jobs are moving around. Even after considering these factors, there are still big differences in productivity levels between regions. This suggests that there are other important factors at play. The researchers also found that the type of industry in each region plays a role in how income is distributed.