Measures of Shifts in Regional Retail Trade

In this paper a new measure or index of retail trade is developed to measure the extent and direction of spatial shifts in retail trade. The index, based on the concepts of market share and concentration, yields static and dynamic measures of shifting retail trade patterns that supplement other retail trade indicators such as pull factors, leakage measures, and per capita sales figures commonly used to analyze intertemporal trade shifts. The technique introduced also is used to judge the relative influence of rural income growth and shifting spatial shopping patterns on the decline in rural retail trade. This is achieved by comparing changes in retail sales and income concentration indexes. Both indexes are calculated from community-level data. Past retail trade research has tended to use community- level retail sales but county-level income data. The empirical evidence presented suggests that the recent decrease in rural retail trade has been due more to shifts in spatial shopping patterns than to declining rural retail purchasing power.