Evans, David K.
Africa Chief Economist’s Office
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Fields of Specialization
Education, Social Development
Africa Chief Economist’s Office
Externally Hosted Work
Last updated July 27, 2023
Bio: David is a Lead Economist in the Chief Economist's Office for the Africa Region of the World Bank. He coordinates impact evaluation work across sectors for the Africa Region. In the past, he worked as Senior Economist in the Human Development Department in the Latin America and the Caribbean Region of the World Bank, and as an economist designing and implementing impact evaluations in Africa. He has designed and implemented impact evaluations in agriculture, education, health, and social protection, in Brazil, the Gambia, Kenya, Mexico, Sierra Leone, and Tanzania. He has taught economic development at the Pardee RAND Graduate School of Public Policy, and he holds a Ph.D. in economics from Harvard University.
Publication Search Results
Now showing 1 - 7 of 7
Publication(World Bank, Washington, DC, 2014-05) Evans, David K. ; Popova, AnnaCash transfers have been demonstrated to improve education and health outcomes and alleviate poverty in various contexts. However, policy makers and others often express concern that poor households will use transfers to buy alcohol, tobacco, or other "temptation goods." The income effect of transfers will increase expenditures if alcohol and tobacco are normal goods, but this may be offset by other effects, including the substitution effect, the effect of social messaging about the appropriate use of transfers, and the effect of shifting dynamics in intra-household bargaining. The net effect is ambiguous. This paper reviews 19 studies with quantitative evidence on the impact of cash transfers on temptation goods, as well as 11 studies that surveyed the number of respondents who reported they used transfers for temptation goods. Almost without exception, studies find either no significant impact or a significant negative impact of transfers on temptation goods. In the only (two, non-experimental) studies with positive significant impacts, the magnitude is small. This result is supported by data from Latin America, Africa, and Asia. A growing number of studies from a range of contexts therefore indicate that concerns about the use of cash transfers for alcohol and tobacco consumption are unfounded.
Publication(World Bank Group, Washington, DC, 2014-09) Evans, David K. ; Popova, AnnaAs evidence from rigorous impact evaluations grows in development, there have been more calls to complement impact evaluation analysis with cost analysis, so that policy makers can make investment decisions based on costs as well as impacts. This paper discusses important considerations for implementing cost-effectiveness analysis in the policy making process. The analysis is applied in the context of education interventions, although the findings generalize to other areas. First, the paper demonstrates a systematic method for characterizing the sensitivity of impact estimates. Second, the concept of context-specificity is applied to cost measurement: program costs vary greatly across contexts -- both within and across countries -- and with program complexity. The paper shows how adapting a single cost ingredient across settings dramatically shifts cost-effectiveness measures. Third, the paper provides evidence that interventions with fewer beneficiaries tend to have higher per-beneficiary costs, resulting in potential cost overestimates when extrapolating to large-scale applications. At the same time, recall bias may result in cost underestimates. The paper also discusses other challenges in measuring and extrapolating cost-effectiveness measures. For cost-effectiveness analysis to be useful, policy makers will require detailed, comparable, and timely cost reporting, as well as significant effort to ensure costs are relevant to the local environment.
Publication(World Bank, Washington, DC, 2015-06) Holland, Peter ; Alfaro, Pablo ; Evans, David K.Countries throughout Latin America and the Caribbean are reforming their education systems with the view of adding more hours to the school day. This paper examines the existing evidence on the relationship between instructional time and student learning, and reviews 15 studies measuring the effects of longer school days. It draws on examples throughout the region to characterize differences in the implementation of extended school day programs, and provides one detailed case study and cost-effectiveness exercise (for Uruguay). While the evidence suggests positive impacts across a range of outcome variables, including gains in student learning, reductions in repetition and dropout, and reductions in teenage pregnancy, there is considerable heterogeneity across programs and studies. Even using the most optimistic impact estimates, a cost-effectiveness exercise suggests that there are likely many more cost-effective reforms to achieve similar effects. The paper concludes with a discussion of the implications for policy makers and practitioners considering an extension of the school day.
Publication(World Bank Group, Washington, DC, 2015-02) Evans, David K. ; Popova, AnnaThe 2014 Ebola Virus Disease outbreak in West Africa is the largest to date by far. Ebola Virus Disease causes disproportionate mortality among the working-age population, resulting in far more mortality for parents of young children than other health crises. This paper combines data on the age distribution of current and projected mortality from Ebola with the fertility distribution of adults in Guinea, Liberia, and Sierra Leone, to estimate the likely impact of the epidemic on the number of orphans in these three countries. Using the latest mortality estimates (from February 11, 2015), it is estimated that more than 9,600 children have lost one or both parents to Ebola Virus Disease. The absolute numbers of orphans created by the Ebola epidemic are significant, but represent a small fraction (1.4 percent) of the existing orphan burden in the affected countries. Ebola is unlikely to increase the numbers of orphans beyond extended family networks' capacities to absorb them. Nonetheless, the pressures of caring for increased numbers of orphans may result in lower quality of care. These estimates should be used to guide policy to support family networks to improve the capacity to provide high quality care to orphans.
Publication(World Bank, Washington, DC, 2015-04) Blimpo, Moussa P. ; Evans, David ; Lahire, NathalieEducation systems in developing countries are often centrally managed in a top-down structure. In environments where schools have different needs and where localized information plays an important role, empowerment of the local community may be attractive, but low levels of human capital at the local level may offset gains from local information. This paper reports the results of a four-year, large-scale experiment that provided a grant and comprehensive school management training to principals, teachers, and community representatives in a set of schools. To separate the effect of the training from the grant, a second set of schools received the grant only with no training. A third set of schools served as a control group and received neither intervention. Each of 273 Gambian primary schools were randomized to one of the three groups. The program was implemented through the government education system. Three to four years into the program, the full intervention led to a 21 percent reduction in student absenteeism and a 23 percent reduction in teacher absenteeism, but produced no impact on student test scores. The effect of the full program on learning outcomes is strongly mediated by baseline local capacity, as measured by adult literacy. This result suggests that, in villages with high literacy, the program may yield gains on students learning outcomes. Receiving the grant alone had no impact on either test scores or student participation.
What Really Works to Improve Learning in Developing Countries?: An Analysis of Divergent Findings in Systematic Reviews(Published by Oxford University Press on behalf of the World Bank, 2016-08) Evans, David K. ; Popova, AnnaOver the course of just two years, at least six reviews have examined interventions that seek to improve learning outcomes in developing countries. Although the reviews ostensibly have the same objective, they reach sometimes starkly different conclusions. The first objective of this paper is to identify why reviews diverge in their conclusions and how future reviews can be more effective. The second objective is to identify areas of overlap in the recommendations of existing reviews of what works to improve learning. This paper demonstrates that divergence in the recommendations of learning reviews is largely driven by differences in the samples of research incorporated in each review. Of 229 studies with student learning results, the most inclusive review incorporates less than half of the total studies. Across the reviews, two classes of programs are recommended with some consistency. Pedagogical interventions that tailor teaching to student learning levels—either teacher-led or facilitated by adaptive learning software—are effective at improving student test scores, as are individualized, repeated teacher training interventions often associated with a specific task or tool. Future reviews will be most useful if they combine narrative review with meta-analysis, conduct more exhaustive searches, and maintain low aggregation of intervention categories.
Publication(World Bank, Washington, DC, 2015-05) Adelman, Melissa ; Baron, Juan D. ; Blimpo, Moussa ; Evans, David K. ; Simbou, Atabanam ; Yarrow, Noah ; Yarrow, NoahThe Haitian education system made substantial improvements in access over the last decade, such that today the majority of Haiti’s children are in school. Despite improvements, the primary education system is highly inefficient: children start primary school 2 years late on average, and fewer than 60 percent will reach the last grade of the cycle. At each school, classroom observations were conducted using the Stallings Classroom Snapshot instrument, and questions about the school calendar and daily schedule asked. The results provide a representative picture of class time and teacher classroom practice in the Nord and Nord Est departments, and while not representative of Haiti as a whole, do provide a starting point for better understanding the major constraint to achieving a high-quality education for all children: the quality of teacher instruction. Section two describes the sample of schools and the stallings instrument; sections three and four present the main results of the classroom observations on teacher time use and pedagogical practices; section five provides estimates of overall class time that students receive; and section six concludes.