Correlated Non-Classical Measurement Errors, ‘Second Best’ Policy Inference and the Inverse Size-Productivity Relationship in Agriculture


Book Description

We show analytically and empirically that non-classical measurement errors in the two key variables in a hypothesized relationship can bias the estimated relationship between them in any direction. Furthermore, if these measurement errors are correlated, correcting for either one alone can aggravate bias in the parameter estimate of interest relative to ignoring mismeasurement in both variables, a ‘second best’ result with implications for a broad class of economic phenomena of policy interest. We illustrate these results empirically by demonstrating the implications of mismeasured agricultural output and plot size for the long-debated (inverse) relationship between size and productivity.





Book Description




Impacts of COVID-19 on food security: Panel data evidence from Nigeria


Book Description

This paper combines pre-pandemic face-to-face survey data with follow up phone surveys collected in April-May 2020 to quantify the overall and differential impacts of COVID-19 on household food security, labor market participation and local food prices in Nigeria. We exploit spatial variation in exposure to COVID-19 related infections and lockdown measures along with temporal differences in our outcomes of interest using a difference-in-difference approach. We find that those households exposed to higher COVID-19 cases or mobility lockdowns experience a significant increase in measures of food insecurity. Examining possible transmission channels for this effect, we find that COVID-19 significantly reduces labor market participation and increases food prices. We find that impacts differ by economic activities and households. For instance, lockdown measures increased households' experience of food insecurity by 12 percentage points and reduced the probability of participation in non-farm business activities by 13 percentage points. These lockdown measures have smaller impacts on wage-related activities and farming activities. In terms of food security, households relying on non-farm businesses, poorer households, those with school-aged children, and those living in remote and conflicted-affected zones have experienced relatively larger deteriorations in food insecurity. These findings can help inform immediate and medium-term policy responses, including social protection policies aiming at ameliorating the impacts of the pandemic, as well as guide targeting strategies of governments and international donor agencies by identifying the most impacted sub-populations.




World Development Report 2021


Book Description

Today’s unprecedented growth of data and their ubiquity in our lives are signs that the data revolution is transforming the world. And yet much of the value of data remains untapped. Data collected for one purpose have the potential to generate economic and social value in applications far beyond those originally anticipated. But many barriers stand in the way, ranging from misaligned incentives and incompatible data systems to a fundamental lack of trust. World Development Report 2021: Data for Better Lives explores the tremendous potential of the changing data landscape to improve the lives of poor people, while also acknowledging its potential to open back doors that can harm individuals, businesses, and societies. To address this tension between the helpful and harmful potential of data, this Report calls for a new social contract that enables the use and reuse of data to create economic and social value, ensures equitable access to that value, and fosters trust that data will not be misused in harmful ways. This Report begins by assessing how better use and reuse of data can enhance the design of public policies, programs, and service delivery, as well as improve market efficiency and job creation through private sector growth. Because better data governance is key to realizing this value, the Report then looks at how infrastructure policy, data regulation, economic policies, and institutional capabilities enable the sharing of data for their economic and social benefits, while safeguarding against harmful outcomes. The Report concludes by pulling together the pieces and offering an aspirational vision of an integrated national data system that would deliver on the promise of producing high-quality data and making them accessible in a way that promotes their safe use and reuse. By examining these opportunities and challenges, the Report shows how data can benefit the lives of all people, particularly poor people in low- and middle-income countries. .




Remote Sensing for Field-based Crop Phenotyping


Book Description

Dynamic monitoring of crop phenotypic traits (e.g., LAI, plant height, biomass, nitrogen, yield et al.) is essential for exploring crop growth patterns, breeding new varieties, and determining optimized strategies for crop management. Traditional methods for determining crop phenotypic traits are mainly based on field sampling, handheld instrument measurement, and mechanized high-throughput platforms, which are time-consuming, and have low efficiency and incomplete spatial coverage. The development of crop science requires more rapid and accurate access to field-based crop phenotypes. Remote sensing provides a novel solution to quantify crop structural and functional traits in a timely, rapid, non-invasive and efficient manner. With the development of burgeoning remote sensing sensors and diversified algorithms, a range of crop phenotypic traits have been determined, including morphological parameters, spectral and textural characteristics, physiological traits, and responses to abiotic/biotic stresses in different environments. In addition, research advances in varying disciplines beyond agricultural sciences, such as engineering, computer science, molecular biology, and bioinformatics, have brought new opportunities for further development of remote sensing-based methods and technologies to gain more quantitative information on crop structure and function in complex environments




Land scarcity impedes sustainable input intensification in smallholder irrigated agriculture: Evidence from Egypt


Book Description

Increasing population pressure and population density in many African countries are inducing land scarcity and land constraints. These increasing land constraints are expected to trigger various responses and adaptation strategies, including agricultural intensification induced by land scarcity, as postulated by the Boserup hypothesis. However, most empirical evaluations of the Boserup hypothesis come from rainfed agriculture and mostly from Sub-Saharan Africa (SSA), where application of improved agricultural inputs remains historically low. Agricultural intensification practices as well as the relevance of the Boserup hypothesis in irrigated agriculture and in contexts where application of improved inputs is high remains unexplored. Furthermore, while much of the debate on the topic in Africa has focused on how to boost agricultural intensification, there is scant evidence on whether evolving agricultural intensification practices in some parts of Africa are sustainable, yield-enhancing, and optimal. In this paper we investigate the implication of land scarcity on agricultural intensification and the relevance of the Boserup hypothesis in the context of Egypt, where agriculture is dominated by irrigation and input application rates are much higher than SSA. We also examine whether evolving agricultural intensification practices induced by land scarcity are agronomically appropriate and yield-enhancing. We find that land scarcity induces higher application of agricultural inputs, mainly nitrogen fertilizers, sometimes beyond the level that is agronomically recommended. More importantly, land scarcity increases overapplication of nitrogen fertilizer relative to crop-specific agronomic recommendations. This implies that land constraints remain as important challenges for sustainable agricultural intensification. Finally, we find suggestive evidence that such overapplication of nitrogen fertilizers is not yield-enhancing, but, rather, yield-reducing. We also document that land scarcity impedes mechanization of agriculture. Our findings have important implications to inform appropriate farm management and sustainable intensification practices. Furthermore, our results can inform long-term policy responses to land scarcity.




Mismeasurement and efficiency estimates: Evidence from smallholder survey data in Africa


Book Description

Smallholder agriculture in sub-Saharan Africa is commonly characterized by high levels of technical inefficiency. However, much of this characterization relies on self-reported input and production data, which are prone to systematic measurement error. We theoretically show that non-classical measurement error introduces multiple identification challenges and sources of bias in estimating smallholders’ technical inefficiency. We then empirically examine the implications of measurement error for the estimation of technical inefficiency using smallholder farm survey data from Ethiopia, Malawi, Nigeria, and Tanzania. We find that measurement error in agricultural input and production data leads to a substantial upward bias in technical inefficiency estimates (by up to 85 percent for some farmers). Our results suggest that existing estimates of technical efficiency in sub-Saharan Africa may be severe underestimates of smallholders’ actual efficiency and what is commonly attributed to farmer inefficiency may be an artifact of mismeasurement in agricultural data. Our results raise questions about the received wisdom on African smallholders’ production efficiency and prior estimates of the productivity of agricultural inputs. Improving the measurement of agricultural data can improve our understanding of smallholders’ production efficiencies and improve the targeting of productivity-enhancing technologies.




Accelerating technical change through ICTs: Evidence from a video-mediated extension experiment in Ethiopia


Book Description

The use of information and communications technologies (ICTs) to address a wide array of development issues has gained considerable attention among governments, practitioners, and researchers in recent years (Lwoga and Sangeda 2019). While early studies focused on mobile phones and text messaging, attention is quickly shifting to other media, including video. Many studies on the use of video as a medium explore how increased access and consumption of information can lead to behavior changes that ultimately result in welfare-improving outcomes. This study explores whether video-mediated extension leads to the increased, sustained uptake of productivity-enhancing agricultural technologies and practices by small-scale farmers. Over the two-year period of 2017–2018, the Government of Ethiopia and Digital Green conducted the large-scale rollout of a video-mediated extension approach. We examine the impact of this rollout on a range of outcome indicators, including whether targeting the video-mediated approach to both spouses of a household was more effective than targeting the (typically male) household head alone. Our main outcomes of interest include farmer uptake of the subject technologies and the yield gains resulting from these technologies. Our study provides insights into the mechanisms behind the observed effects and an analysis of the approach’s cost effectiveness. Our results demonstrate that the video-mediated extension approach led to increases in farmer uptake of improved agricultural technologies and practices. In the first year of the experiment, we find an overall 6 percentage point increase in technology uptake, which translates into a 10 percent increase over the mean of the control group. An analysis of uptake by type of technology shows that the video-mediated approach resulted in an increase of 13, 20, and 15 percent over control group means for row planting, precise seeding rate, and urea top/side dressing, respectively. These results endure in the second year of the experiment, pointing to farmers’ effective uptake of the technology beyond a mere trial in one production season. Upon exploring the mechanisms that explain these adoption effects, we find that the video-mediated extension approach led to an increase in extension reach, with a 35 percent increase in farmers’ attendance at extension sessions (likely due to interest in the video medium). Among farmers assigned to the video-mediated extension approach, we also find a higher level of technical understanding of focal agricultural technologies and practices. While our results suggest greater participation and knowledge gains among (typically female) spouses who also participated in the video-mediated extension approach, we do not find clear evidence that targeting both spouses led to higher rates of technology uptake.




Ethiopia's agrifood system: Past trends, present challenges, and future scenarios


Book Description

Ethiopia has experienced impressive agricultural growth and poverty reduction, stemming in part from substantial public investments in agriculture. Yet, the agriculture sector now faces increasing land and water constraints along with other challenges to growth. Ethiopia’s Agrifood System: Past Trends, Present Challenges, and Future Scenarios presents a forward-looking analysis of Ethiopia’s agrifood system in the context of a rapidly changing economy. Growth in the agriculture sector remains essential to continued poverty reduction in Ethiopia and will depend on sustained investment in the agrifood system, especially private sector investment. Many of the policies for a successful agricultural and rural development strategy for Ethiopia are relevant for other African countries, as well. Ethiopia’s Agrifood System should be a valuable resource for policymakers, development specialists, and others concerned with economic development in Africa south of the Sahara.




Assessing response fatigue in phone surveys: Experimental evidence on dietary diversity in Ethiopia


Book Description

The COVID-19 pandemic has spurred interest in the use of remote data collection techniques, including phone surveys, in developing country contexts. This interest has sparked new methodological work focusing on the advantages and disadvantages of different forms of remote data collection, the use of incentives to increase response rates and how to address sample representativeness. By contrast, attention given to associated response fatigue and its implications remains limited. To assess this, we designed and implemented an experiment that randomized the placement of a survey module on women’s dietary diversity in the survey instrument. We also examine potential differential vulnerabilities to fatigue across food groups and respondents. We find that delaying the timing of mothers’ food consumption module by 15 minutes leads to 8-17 percent decrease in the dietary diversity score and a 28 percent decrease in the number of mothers who consumed a minimum of four dietary groups. This is driven by underreporting of infrequently consumed foods; the experimentally induced delay in the timing of mothers’ food consumption module led to a 40 and 11 percent decrease in the reporting of consumption of animal source foods, and fruits and vegetables, respectively. Our results are robust to changes in model specification and pass falsification tests. Responses by older and less educated mothers and those from larger households are more vulnerable to measurement error due to fatigue.