Author Name Variants
Fields of Specialization
Poverty and growth, Program evaluation, Social impact of public policy
Externally Hosted Work
Last updated January 31, 2023
B. Essama-Nssah worked for 17 years for the World Bank in Washington, DC, before he retired as a senior economist in 2011. During his tenure at the Bank, he performed economic analyses, prepared policy research and technical papers, and conducted an annual training course on impact evaluation methodologies for staff from the World Bank and client countries. Before joining the World Bank, Essama-Nssah worked for two years as a senior research associate on the Food and Nutrition Program at Cornell University, and for six years as head of the Economics Department and vice dean of the Faculty of Law and Economics of the University of Yaoundé, Cameroon. He currently works as a consultant focusing on poverty and growth incidence analysis, program evaluation, and analysis of the social impact of public policy. He holds a PhD in economics from the University of Michigan in Ann Arbor.
Publication Search Results
Now showing 1 - 10 of 20
Publication(Taylor and Francis, 2012-11-20) Skoufias, Emmanuel ; Katayama, Roy S. ; Essama-Nssah, B.We use regression analysis to assess the potential welfare impacts in rural Indonesia of two types of shock: a delay in monsoon onset; and a significant shortfall in rain during the 90-day post-onset period. Focusing on households with family farm businesses, we find that a delay in monsoon onset does not have a significant effect on the welfare of rice farmers. However, rice farm households located in areas exposed to low rainfall following the monsoon are negatively affected. Such households appear to be able to protect their food expenditure in the face of weather shocks, but at the expense of their non-food expenditure. We also use propensity score matching to identify community programs that might moderate the impact of this type of shock. We find that access to credit and public works projects has the strongest moderating effect. This is an important consideration for the design and implementation of adaptation strategies.
Publication(World Bank, Washington, D.C., 2004-09) Essama-Nssah, B.Starting with a general impact indicator as an evaluation criterion, The author offers an integrative framework for a unified discussion of various concepts and measures of pro-poor growth emerging from the current literature. He shows that whether economic growth is considered pro-poor depends fundamentally on the choice of evaluative weights. In addition, the author's framework leads to a new indicator of the rate of pro-poor growth that can be interpreted as the equally distributed equivalent growth rate. This is a distribution-adjusted rate of growth that depends on the chosen level of inequality aversion. Illustrations based on data for Indonesia in the 1990s show a strong link between growth and poverty reduction in that country. A decomposition of the observed poverty outcomes reveals the extent to which changes in inequality have blunted the poverty impacts of both growth and contraction. Finally, the results also demonstrate that absolute and relative indicators of pro-poor growth can lead to conflicting conclusions from the same set of facts.
Publication(World Bank, Washington, DC, 2004-01) Essama-Nssah, B.A crucial step in policy analysis involves computing consequences of policy actions. The author shows how to implement numerically a general equilibrium model in EViews. Computable general equilibrium models are now commonly used in both industrial and developing countries to assess the impact of external shocks or economic policies on the structure of the economy or the distribution of welfare. The current version of EViews offers a set of tools for building and solving simulation models in general. The same tools make it possible to conduct policy analysis within a general equilibrium framework. Based on the generalized Salter-Swan framework and macroeconomic data for Indonesia, the author shows how to process a social accounting matrix, specify and calibrate the model, and run simulations. The results replicate welfare and structural effects of shocks and policies consistent with the underlying conceptual framework. They also reveal the key role played by structural parameters, such as the elasticity of export transformation and that of import substitution, in determining the extent of structural adjustment to shocks and the relevance of the policy response.
Publication(World Bank, Washington, DC, 2002-09) Pereira da Silva, Luiz A. ; Essama-Nssah, B. ; Samake, IssoufThe Poverty Analysis Macroeconomic Simulator (PAMS) is a model that links standard household surveys with macro frameworks. It allows users to assess the effect of macroeconomic policies-in particular, those associated with Poverty Reduction Strategies papers-on sectoral employment and income, the incidence of poverty, and income distribution. PAMS (in Excel) has three interconnected components: (1) A standard aggregate macro-framework that can be taken from any macro-consistency model (for example, RMSM-X, 123) to project GDP, national accounts, the national budget, the BoP, price levels, and so on, in aggregate consistent accounts. (2) A labor market model breaking down labor categories by skill level and economic sectors whose production total is consistent with that of the macro framework. Individuals from the household surveys are grouped in representative groups of households defined by the labor category of the head of the household. For each labor category, labor demand depends on sectoral output and real wages. Wage income levels by economic sector and labor category can thus be determined. In addition, different income tax rates and different levels of budgetary transfers across labor categories can be added to wage income. (3) A model that uses the labor model results for each labor category to simulate the income growth for each individual inside its own group, assumed to be the average of its group. After projecting individual incomes, PAMS calculates the incidence of poverty and the inter-group inequality. PAMS can produce historical or counterfactual simulations of: + Alternative growth scenarios with different assumptions for inflation, fiscal, and current account balances. These simulations allow test tradeoffs within a macro stabilization program. + Different combinations of sectoral growth (agricultural or industrial, tradable or non-tradable goods sectors), within a given aggregate GDP growth rate. + Tax and budgetary transfer policies. For example, PAMS will simulate a baseline macro-scenario for Burkina Faso corresponding to an existing IMF/World Bank-supported program and introduce changes in tax, fiscal, and sectoral growth policies to reduce poverty and inequality more effectively than the base scenario. So, the authors argue that there are several possible "equilibria" in terms of poverty and inequality within the same macro framework.
Publication(World Bank, Washington, DC, 2002-09) Essama-Nssah, B.Economic development necessarily changes the welfare of socioeconomic groups to various degrees, depending on differences in their social arrangements. The challenge for policymakers is to select the changes that will be most socially desirable. The author demonstrates the usefulness of distributional analysis for social evaluation and, more specifically, for welfare evaluation, using data from the 1994 Integrated Household Survey in Guinea. Because the international community has declared poverty eradication a fundamental objective of development, the author uses a poverty-focused approach to social evaluation based on the maximum principle. This principle offers a unifying framework for analyzing the socioeconomic impact of public policy by using a wide variety of evaluation functions, inequality indicators (like the extended Gini coefficient), and poverty indices (such as Sen's index and the members of the Foster-Greer-Thorbecke family). The author also examines, within the context of commodity taxation, how to identify socially desirable policy options using both the dominance criterion and abbreviated social welfare functions. He includes computer routines for calculating various welfare indices and for plotting the relevant concentration curves.
Publication(World Bank, Washington, DC, 2007-06) Essama-Nssah, B.The difficulties faced by many developing countries in raising revenue from direct taxes have forced them to rely heavily on indirect taxes to finance development interventions. The purpose of this paper is to show how to identify socially desirable options for commodity taxation in the context of a poverty reduction strategy. Within the logic of social evaluation the author assesses tax options on the basis of value judgments underlying members of the additively separable class of poverty measures. The criterion hinges on both the pattern of consumption of each commodity and the price elasticity of the poverty measure used. An application of this methodology to data for Guinea shows that many components of food expenditure (particularly cereals, grains, and roots) would be good candidates for exemption from value-added tax. Even though expenditure on health and education is distributed in favor of the non-poor, their importance for human capital development argues for a program of targeted subsidies in a broader context of cost recovery.
Publication(World Bank, Washington, DC, 2008-03) Essama-Nssah, B. ; Ezemenari, Kene ; Korman, VijdanThe Poverty Reduction Strategy of the Government of Rwanda seeks to unlock the growth and poverty reduction potential of the tea sector through the privatization of tea estates. This paper uses the logic of causal inference and data from the 2004 Quantitative Baseline Survey of the tea sector to assess the potential impact of the privatization program. This entails a normalized comparison of productivity outcomes to account for household heterogeneity in terms of observable and non-observable determinants of these outcomes. The paper also compares living standards between tea and non-tea households. Three main findings emerge from the analysis. Productivity outcomes are generally better in the private sector than in the public sector. Male-headed households outperform female-headed households along all dimensions considered here. And tea households tend to be better off than non-tea households.
Publication(World Bank, Washington, DC, 2007-09) Essama-Nssah, B. ; Go, Delfin S. ; Kearney, Marna ; Korman, Vijdan ; Robinson, Sherman ; Thierfelder, KarenAs crude oil prices reach new highs, there is renewed concern about how external shocks will affect growth and poverty in developing countries. This paper describes a macro-micro framework for examining the structural and distributional consequences of a significant external shock-an increase in the world price of oil-on the South African economy. The authors merge results from a highly disaggregative computable general equilibrium model and a micro-simulation analysis of earnings and occupational choice based on socio-demographic characteristics of the household. The model provides changes in employment, wages, and prices that are used in the micro-simulation. The analysis finds that a 125 percent increase in the price of crude oil and refined petroleum reduces employment and GDP by approximately 2 percent, and reduces household consumption by approximately 7 percent. The oil price shock tends to increase the disparity between rich and poor. The adverse impact of the oil price shock is felt by the poorer segment of the formal labor market in the form of declining wages and increased unemployment. Unemployment hits mostly low and medium-skilled workers in the services sector. High-skilled households, on average, gain from the oil price shock. Their income rises and their spending basket is less skewed toward food and other goods that are most affected by changes in oil prices.
Publication(World Bank, Washington, DC, 2006-10) Essama-Nssah, B. ; Lambert, Peter J.Poverty reduction has become a fundamental objective of development, and therefore a metric for assessing the effectiveness of various interventions. Economic growth can be a powerful instrument of income poverty reduction. This creates a need for meaningful ways of assessing the poverty impact of growth. This paper follows the elasticity approach to propose a measure of pro-poorness defined as a weighted average of the deviation of a growth pattern from the benchmark case. The measure can help assess pro-poorness both in terms of aggregate poverty measures, which are members of the additively separable class, and at percentiles. It also lends itself to a decomposition procedure, whereby the overall pattern of income growth can be unbundled, and the contributions of income components to overall pro-poorness identified. An application to data for Indonesia in the 1990s reveals that the amount of poverty reduction achieved over that period remains far below what would have been achieved under distributional neutrality. This conclusion is robust to the choice of a poverty measure among members of the additively separable class, and can be tracked back to changes in expenditure components.
Publication(World Bank, Washington, DC, 2006-04) Essama-Nssah, B.Effective development policymaking creates a need for reliable methods of assessing effectiveness. There should be, therefore, an intimate relationship between effective policymaking and impact analysis. The goal of a development intervention defines the metric by which to assess its impact, while impact evaluation can produce reliable information on which policymakers may base decisions to modify or cancel ineffective programs and thus make the most of limited resources. This paper reviews the logic of propensity score matching (PSM) and, using data on the National Support Work Demonstration, compares that approach with other evaluation methods such as double difference, instrumental variable, and Heckman's method of selection bias correction. In addition, it demonstrates how to implement nearest-neighbor and kernel-based methods, and plot program incidence curves in E-Views. In the end, the plausibility of an evaluation method hinges critically on the correctness of the socioeconomic model underlying program design and implementation, and on the quality and quantity of available data. In any case, PSM can act as an effective adjuvant to other methods.