Measuring the impact of road rehabilitation on spatial market efficiency in maize markets in Mozambique

This article analyzes the impact of road rehabilitation on the spatial market efficiency of maize markets in Mozambique. We estimate a modified version of the Parity Bounds Model (PBM) that allows us to test the impact of road rehabilitation on spatial efficiency. This article seeks to contribute to the existing literature in three ways. First, a unique data set, where road rehabilitation episodes between market pairs are identified, is developed. Second, special care is devoted to estimation of transaction costs due to the sensitivity of the PBM model to the quality of transaction costs estimates. Finally, as opposed to most existing literature that focuses on relatively distant markets, the article focuses on spatially closed markets. We find that maize markets tend to be segmented due to high transport costs. Following road rehabilitation, inefficiency and average absolute price differentials tend to decrease, and market pairs have tended to shift toward autarky regimes. Overall, while the results point broadly toward a positive impact of road rehabilitation on spatial efficiency, they are not as strong or as robust as one would like. Large increases in fuel prices likely offset the positive impacts of road rehabilitation on transaction costs, contributing to the increase in the probability of being in an autarky regime.