Evans School Policy Analysis & Research Group (EPAR)

Precise agricultural statistics are necessary to track productivity and design sound agricultural policies. Yet, in settings where intercropping is prevalent, even crop yield can be challenging to measure. In a systematic survey of the literature on crop yield in low-income settings, we find that scholars specify how they estimate the yield denominator in under 10% of cases. Using household survey data from Tanzania, we consider four alternative methods of allocating land area on plots that contain multiple crops, and explore the implications of this measurement decision for analyses of maize and rice yield. We find that 64% of cultivated plots contain more than one crop, and average yield estimates vary with different methods of calculating area planted. This pattern is more pronounced for maize, which is more likely than rice to share a plot with other crops. The choice among area methods influences which of these two staple crops is found to be more calorie-productive per ha, as well as the extent to which fertilizer is expected to be profitable for maize production. Given that construction decisions can influence the results of analysis, we conclude that the literature would benefit from greater clarity regarding how yield is measured across studies.

Donor countries and multilateral organizations may pursue multiple goals with foreign aid, including supporting low-income country development for strategic/security purposes (national security, regional political stability) and for short-and long-term economic interests (market development and access, local and regional market stability). While the literature on the effectiveness of aid in supporting progress on different indicators of country development is inconclusive, donors are interested in evidence that aid funding is not permanent but rather contributes to a process by which recipient countries develop to a point that they are economically self-sufficient. In this report, we review the literature on measures of country self-sufficiency and descriptive evidence from illustrative case studies to explore conditions associated with transitions toward self-sufficiency in certain contexts.

Common aid allocation formulas incorporate measures of income per capita but not measures of poverty, likely based on the assumption that rising average incomes are associated with reduced poverty. If declining poverty is the outcome of interest, however, the case of Nigeria illustrates that such aid allocation formulas could lead to poorly targeted or inefficient aid disbursements. Using data from the World Bank and the Nigerian National Bureau of Statistics, we find that while the relationship between economic growth and poverty in Nigeria varies depending on the time period studied, overall from 1992-2009 Nigeria’s poverty rate has only declined by 6% despite a 70% increase in per capita gross domestic product (GDP). A review of the literature indicates that income inequality, the prominence of the oil sector, unemployment, corruption, and poor education and health in Nigeria may help to explain the pattern of high ongoing poverty rates in the country even in the presence of economic growth. Our analysis is limited by substantial gaps in the availability of quality data on measures of poverty and economic growth in Nigeria, an issue also raised in the literature we reviewed, but our findings support arguments that economic growth should not be assumed to lead to poverty reduction and that the relationship between these outcomes likely depends on contextual factors.

This research brief synthesizes evidence on the effects of policy incentives on agricultural productivity. The evidence discussed is primarily drawn from documents provided to EPAR by the Bill and Melinda Gates Foundation. We review the role of policy and institutions in the Asian Green Revolution, a detailed case study on how policy changes have removed smallholder productivity constraints and contributed to growth, and the theory on the connection of policy incentives to productivity growth.