Evans School Policy Analysis & Research Group (EPAR)

Household survey data are a key source of information for policy-makers at all levels. In developing countries, household data are commonly used to target interventions and evaluate progress towards development goals. The World Bank’s Living Standards Measurement Study - Integrated Surveys on Agriculture (LSMS-ISA) are a particularly rich source of nationally-representative panel data for six Sub-Saharan African countries: Ethiopia, Malawi, Niger, Nigeria, Tanzania, and Uganda. To help understand how these data are used, EPAR reviewed the existing literature referencing the LSMS-ISA and identified 415 publications, working papers, reports, and presentations with primary research based on LSMS-ISA data. We find that use of the LSMS-ISA has been increasing each year since the first survey waves were made available in 2009, with several universities, multilateral organizations, government offices, and research groups across the globe using the data to answer questions on agricultural productivity, farm management, poverty and welfare, nutrition, and several other topics.

This four-part analysis describes the current suite of food security measures, then analyzes the respective relationships between food security and poverty, GDP, and crop yields using findings from in-depth literature reviews. Food security measures are criticized for inaccurately characterizing food security at individual, household, and national scales, yet guidelines exist to prescribe a food security measure for a given situation. Some authors see the potential of a combination of indicators that apply at different scales rather than a single, universal food security measure. Limited literature exists on the relationship between food security and poverty, GDP, or crop yields. The relationship between food security and poverty is particularly challenging because neither term has a consistent definition, and the limited literature suggests a lack of consensus among experts. Little empirical research exists on the relationship between food security and GDP, though studies generally note an association between the two Studies that evaluate food security and crop yields provide limited evidence that the two are associated, though many studies use measures of crop yield as food security indicators and vice versa. More research is needed to establish whether there are preferred food security measurement tools for specific scales and situations, and to further explore the relationship between food security and poverty, GDP, and crop yields.

Common estimates of agricultural productivity rely upon crude measures of crop yield, typically defined as the weight harvested of a crop divided by the area harvested. But this common yield measure poorly reflects performance among farm systems combining multiple crops in one area (e.g., intercropping), and also ignores the possibility that farmers might lose crop area between planting and harvest (e.g., partial crop failure). Drawing on detailed plot-level data from Tanzania’s National Panel Survey, our research contrasts measures of smallholder productivity using production per hectare harvested and production per hectare planted.

An initial analysis (Research Brief - Rice Productivity Measurement) looking at rice production finds that yield by area planted differs significantly from yield by area harvested, particularly for smaller farms and female-headed households. OLS regression further reveals different demographic and management-related drivers of variability in yield gains – and thus different implications for policy and development interventions – depending on the yield measurement used. Findings suggest a need to better specify “yield” to more effectively guide agricultural development efforts.

This brief reviews the evidence of realized yield gains by smallholder farmers attributable to the use of high-quality seed and/or improved seed varieties. Our analysis suggests that in most cases, use of improved varieties and/or quality seed is associated with modest yield increases.  In the sample of 395 trials reviewed, positive yield changes accompanied the use of improved variety or quality seed, on average, in 10 out of 12 crops, with rice and cassava as the two exceptions.