Suburban development derives from outward expansion of cities, often driven by sought profit and the availability of cheap land. This change in consumption causes a fall in inner city land prices, often resulting in poor upkeep and a neglect of repair for these properties by owners and landlords. The depressed land is then devalued, causing rent to be significantly cheaper than the potential rent that could be derived from the "best use" of the land while taking advantage of its central location. From this derives the "Rent-gap Theory" describing the disparity between "the actual capitalized ground rent (land price) of a plot of land given its present use, and the potential ground rent that might be gleaned under a 'higher and better' use."