Assessment of Water Use Efficiency in Sub-Sahara Africa : Application of The Malmquist Productivity Index

This paper presents the assessment of improvement in water use efficiency in sub-Sahara Africa based on the Malmquist Productivity Index (MPI). The study was conducted in 28 countries in sub-Sahara Africa from 2007 to 2017. Two test cases comprising data with water stress as undesired output, and without water stress as undesired output were analyzed to determine their level of impact on the improvement of water use efficiency. Again the technical efficiency as well as technological efficiency change were examined. The overall mean outcome of the results regarding the test case of the MPI with the inclusion of water stress was 0.969 which is higher than the values recorded from 2012-2016. Comparing the two results, it was observed that the mean MPI estimates without water stress are much higher than that of the average MPI with the inclusion of water stress. This means that without the inclusion of undesirable factors such as water stress, the MPI scores could be overestimated. In terms of the catch-up effect, all sampled countries were technically efficient except Angola, Burundi, Chad, Madagascar, Mauritania, Mozambique, Sierra Leone and Togo which could not meet the efficiency frontier of 1.00. With the technological efficiency change, the results indicated that none of the sampled countries was able to reach the efficiency frontier. Policy recommendations based on the results are provided. Keywords : Water Use Efficiency, Water Stress, Improvement, Malmquist Productivity Index, Data Envelopment Analysis, Sub-Sahara Africa