Economic growth and development are higher in metro areas where density is most concentrated. In a recent survey, author Richard Florida studied the role of density in regional economic development, especially in cities where population is more densely concentrated in and around their cores. Cities and regions where density is more concentrated appear to gain the biggest economic advantage. Florida also found that happiness levels are modestly associated with density that is more concentrated at the center of the city.
To learn more: http://www.theatlanticcities.com/jobs-and-economy/2012/11/cities-denser-cores-do-better/3911/#.ULYzLULZ_CU.gmail