Marges à travers le temps et l'espace : détermination spatiale des prix sur les marchés de produits agricoles en Tanzanie

Distance and transfer costs determine the price received or paid by farmers in developing countries. High margins reduce the area over which food is marketed, often insulating regions and households from price signals. This reduction in price information may result in inefficient outcomes. This paper focuses on two approaches analyzing spatial price relationships and margins in Tanzania. Threshold cointegration provides a method for assessing the extent of market integration between different regions, but also for approximating the magnitude of transport and other transaction costs. Spatial pricing focuses on identifying the determinants of margins, in terms of distance, the quality of transport and communication infrastructure. We use threshold cointegration to investigate the relationship between prices in a number of well-connected and remote markets in Tanzania. A spatial price model aiming to assess the determinants of margins, including market power, is applied on a cross section data set based on a representative survey of rural households in the Kilimanjaro and Ruvuma regions. Although, threshold cointegration suggests that regional markets in the country are integrated, the spatial market model provides some support for the effect of distance and transport infrastructure on the prices received by farmers.