Community planners in Illinois use computer software to conduct retail trade market analyses based on Reilly's Law. Market boundaries are determined using the population of the town and neighboring town, and the distance between the two towns. The simple indices implied by Reilly's Law do not offer reliable guidance to planners. (KS)

Changes in national demographics have altered how we define community. The community may be a geographic area of home life, a place for coming together voluntarily, or an association of people with similar interests and values. New communities must develop their own infrastructures and capacities for sustaining themselves. (SLD)